MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'American Journal of Epidemiology' source. Thu, 09 Feb 2012 11:21:02 +0100 http://www.medworm.com/index.php?rid=5655004&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F360%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5655004 Fri, 03 Feb 2012 05:00:00 +0100 5655004 http://www.medworm.com/index.php?rid=5655003&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F359%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5655003 Fri, 03 Feb 2012 05:00:00 +0100 5655003 http://www.medworm.com/index.php?rid=5655002&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F348%3Frss%3D1 Information on dietary supplements, medications, and other xenobiotics in epidemiologic surveys is usually obtained from questionnaires and is subject to recall and reporting biases. The authors used metabolite data obtained from hydrogen-1 (or proton) nuclear magnetic resonance (1H NMR) analysis of human urine specimens from the International Study of Macro-/Micro-Nutrients and Blood Pressure (INTERMAP Study) to validate self-reported analgesic use. Metabolic profiling of two 24-hour urine specimens per individual was carried out for 4,630 participants aged 40–59 years from 17 population samples in Japan, China, the United Kingdom, and the United States (data collection, 1996–1999). 1H NMR-detected acetaminophen and ibuprofen use was low (~4%) among East Asian population sampl... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5655002 Fri, 03 Feb 2012 05:00:00 +0100 5655002 http://www.medworm.com/index.php?rid=5655001&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F340%3Frss%3D1 With the advent of Internet-based 24-hour recall (24HR) instruments, it is now possible to envision their use in cohort studies investigating the relation between nutrition and disease. Understanding that all dietary assessment instruments are subject to measurement errors and correcting for them under the assumption that the 24HR is unbiased for usual intake, here the authors simultaneously address precision, power, and sample size under the following 3 conditions: 1) 1–12 24HRs; 2) a single calibrated food frequency questionnaire (FFQ); and 3) a combination of 24HR and FFQ data. Using data from the Eating at America’s Table Study (1997–1998), the authors found that 4–6 administrations of the 24HR is optimal for most nutrients and food groups and that combined use ... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5655001 Fri, 03 Feb 2012 05:00:00 +0100 5655001 http://www.medworm.com/index.php?rid=5655000&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F332%3Frss%3D1 As with other instrumental variable (IV) analyses, Mendelian randomization (MR) studies rest on strong assumptions. These assumptions are not routinely systematically evaluated in MR applications, although such evaluation could add to the credibility of MR analyses. In this article, the authors present several methods that are useful for evaluating the validity of an MR study. They apply these methods to a recent MR study that used fat mass and obesity-associated (FTO) genotype as an IV to estimate the effect of obesity on mental disorder. These approaches to evaluating assumptions for valid IV analyses are not fail-safe, in that there are situations where the approaches might either fail to identify a biased IV or inappropriately suggest that a valid IV is biased. Therefore, the authors d... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5655000 Fri, 03 Feb 2012 05:00:00 +0100 5655000 http://www.medworm.com/index.php?rid=5654999&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F325%3Frss%3D1 Regression calibration has been described as a means of correcting effects of measurement error for normally distributed dietary variables. When foods are the items of interest, true distributions of intake are often positively skewed, may contain many zeroes, and are usually not described by well-known statistical distributions. The authors considered the validity of regression calibration assumptions where data are non-Gaussian. Such data (including many zeroes) were simulated, and use of the regression calibration algorithm was evaluated. An example used data from Adventist Health Study 2 (2002–2008). In this special situation, a linear calibration model does (as usual) at least approximately correct the parameter that captures the exposure-disease association in the "disease" mod... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5654999 Fri, 03 Feb 2012 05:00:00 +0100 5654999 http://www.medworm.com/index.php?rid=5654998&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F315%3Frss%3D1 In this report, the authors delineate the study’s objectives, principal methodological features, and timeline. At baseline, ELSA-Brasil enrolled 15,105 civil servants from 5 universities and 1 research institute. The baseline examination (2008–2010) included detailed interviews, clinical and anthropometric examinations, an oral glucose tolerance test, overnight urine collection, a 12-lead resting electrocardiogram, measurement of carotid intima-media thickness, echocardiography, measurement of pulse wave velocity, hepatic ultrasonography, retinal fundus photography, and an analysis of heart rate variability. Long-term biologic sample storage will allow investigation of biomarkers that may predict cardiovascular diseases and diabetes. Annual telephone surveillance, initiated in ... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5654998 Fri, 03 Feb 2012 05:00:00 +0100 5654998 http://www.medworm.com/index.php?rid=5654997&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F309%3Frss%3D1 The authors conducted a nationwide cohort study to evaluate the association between postmenopausal hormone therapy and meningioma incidence in Finland. All women who had used hormone therapy at least for 6 months at the age of 50 years or older during 1994–2009 were included. Women who had used postmenopausal hormone therapy were identified from the medical reimbursement register of the Social Insurance Institution (131,480 estradiol users and 131,248 estradiol-progestin users), and meningioma cases were identified from the Finnish Cancer Registry. During the average 9 years of follow-up, 289 estradiol users and 196 estradiol-progestin users were diagnosed with meningioma. Ever use of estradiol-only therapy was associated with an increased risk of meningioma (standardized incidence r... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5654997 Fri, 03 Feb 2012 05:00:00 +0100 5654997 http://www.medworm.com/index.php?rid=5654996&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F302%3Frss%3D1 This study examined associations between mortality and demographic and risk characteristics among young injection drug users in San Francisco, California, and compared the mortality rate with that of the population. A total of 644 young (<30 years) injection drug users completed a baseline interview and were enrolled in a prospective cohort study, known as the UFO ("U Find Out") Study, from November 1997 to December 2007. Using the National Death Index, the authors identified 38 deaths over 4,167 person-years of follow-up, yielding a mortality rate of 9.1 (95% confidence interval: 6.6, 12.5) per 1,000 person-years. This mortality rate was 10 times that of the general population. The leading causes of death were overdose (57.9%), self-inflicted injury (13.2%), trauma/accidents (10.5%), a... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5654996 Fri, 03 Feb 2012 05:00:00 +0100 5654996 http://www.medworm.com/index.php?rid=5654995&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F289%3Frss%3D1 The association between passive cigarette smoke exposure and breast cancer risk is inconclusive and may be modified by genotype. The authors investigated lifetime passive cigarette smoke exposures, 36 variants in 12 carcinogen-metabolizing genes, and breast cancer risk among Ontario, Canada, women who had never smoked (2003–2004). DNA (saliva) was available for 920 breast cancer cases and 960 controls. Detailed information about passive smoke exposure was collected for multiple age periods (childhood, teenage years, and adulthood) and environments (home, work, and social). Adjusted odds ratios and 95% confidence intervals were estimated by multivariable logistic regression, and statistical interactions were assessed using the likelihood ratio test. Among postmenopausal women, most as... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5654995 Fri, 03 Feb 2012 05:00:00 +0100 5654995 http://www.medworm.com/index.php?rid=5654994&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F279%3Frss%3D1 Children with asthma can experience chronic morbidity that may interfere with education and career progression. The authors investigated retrospectively whether a history of childhood asthma is associated with educational level and longest-held occupation, by gender. Cross-sectional analysis included a nationally representative sample of 10,452 adults aged ≥20 years who participated in the US National Health and Nutrition Examination Survey (2001–2004). Logistic regression was used to assess associations between a childhood-asthma history and educational level, employment, and longest-held occupation. An estimated 6.9% of men and 5.8% of women had a childhood-asthma history. Persons with a childhood-asthma history tended to have a higher educational level than those with no asthma... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5654994 Fri, 03 Feb 2012 05:00:00 +0100 5654994 http://www.medworm.com/index.php?rid=5654993&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F276%3Frss%3D1 Studies of the relation between exposure to drinking water disinfection by-products and pregnancy outcomes have been limited by the complexity of the exposure itself (consisting of hundreds of different chemicals), the diverse pathways contributing to exposure, and the difficulty in assessing behavioral determinants of exposure. Therefore, exposure biomarkers offer great promise of enhancing exposure assessment, the limiting factor in the quality and conclusiveness of epidemiologic studies. However, there are significant conceptual and logistical challenges in developing biomarkers for the various constituents of concern that are sensitive to typical variation in exposure, reflective of the time periods of interest, not susceptible to interference from exposures other than water, not subje... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5654993 Fri, 03 Feb 2012 05:00:00 +0100 5654993 http://www.medworm.com/index.php?rid=5654992&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F263%3Frss%3D1 Although prenatal exposure to water disinfection by-products does not appear to affect the duration of gestation, its impact on fetal growth remains an open question. The authors studied the associations between prenatal exposure to disinfection by-products and fetal growth restriction (FGR) and preterm birth in the PELAGIE cohort, a French birth cohort comprising 3,421 pregnant women recruited between 2002 and 2006. Exposure was assessed by estimating levels of trihalomethanes (THMs) in tap water during pregnancy and maternal water use and by measuring maternal urinary levels of trichloroacetic acid (TCAA) during early pregnancy in a nested case-control design that compared 174 FGR cases, 114 preterm births, and 399 controls. Higher uptake of THMs (especially brominated THMs) was associat... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5654992 Fri, 03 Feb 2012 05:00:00 +0100 5654992 http://www.medworm.com/index.php?rid=5654991&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F250%3Frss%3D1 Randomized clinical trials (RCTs) are usually the preferred strategy with which to generate evidence of comparative effectiveness, but conducting an RCT is not always feasible. Though observational studies and RCTs often provide comparable estimates, the questioning of observational analyses has recently intensified because of randomized-observational discrepancies regarding the effect of postmenopausal hormone replacement therapy on coronary heart disease. Reanalyses of observational data that excluded prevalent users of hormone replacement therapy led to attenuated discrepancies, which begs the question of whether exclusion of prevalent users should be generally recommended. In the current study, the authors evaluated the effect of excluding prevalent users of statins in a meta-analysis ... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5654991 Fri, 03 Feb 2012 05:00:00 +0100 5654991 http://www.medworm.com/index.php?rid=5654990&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2F245%3Frss%3D1 The objective of the present commentary is to suggest that epidemiologists explore the use of anti-Müllerian hormone (AMH) as a new measurement tool in fecundability studies. The authors briefly summarize the advantages and limitations of the 3 current approaches to studies of fecundability. All 3 approaches involve the collection of time-to-pregnancy or attempt-time data, and most are limited to participants who plan their pregnancies. AMH is produced by ovarian follicles during their early growth stages and is measured clinically to assess ovarian reserve (the number of remaining oocytes). Unlike time to pregnancy, serum AMH level can be assessed regardless of pregnancy-attempt status. Measurements are not significantly affected by phase of the menstrual cycle, oral contraceptive us... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5654990 Fri, 03 Feb 2012 05:00:00 +0100 5654990 http://www.medworm.com/index.php?rid=5654989&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2FNP-c%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5654989 Fri, 03 Feb 2012 05:00:00 +0100 5654989 http://www.medworm.com/index.php?rid=5654988&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2FNP-b%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5654988 Fri, 03 Feb 2012 05:00:00 +0100 5654988 http://www.medworm.com/index.php?rid=5654987&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2FNP-a%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5654987 Fri, 03 Feb 2012 05:00:00 +0100 5654987 http://www.medworm.com/index.php?rid=5654986&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F4%2FNP%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5654986 Fri, 03 Feb 2012 05:00:00 +0100 5654986 http://www.medworm.com/index.php?rid=5615802&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F3%2F236%3Frss%3D1 The anticarcinogenic potential of vitamin D might be mediated by not only calcium metabolism but also other mechanisms initiated by vitamin D receptor (VDR). The authors measured plasma 25-hydroxyvitamin D in healthy volunteer examinees who underwent total colonoscopy in Tokyo, Japan, 2004–2005, and evaluated its influence on colorectal adenoma, both alone and in interaction with VDR polymorphisms, which correspond to the FokI and TaqI restriction sites. The main analysis of plasma 25-hydroxyvitamin D included 737 cases and 703 controls. Compared with the lowest quintile of plasma 25-hydroxyvitamin D, only the highest was related to a significantly decreased odds ratio of colorectal adenoma (odds ratio = 0.64, 95% confidence interval: 0.45, 0.92). In contrast, all but the lowest quin... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5615802 Wed, 18 Jan 2012 05:00:00 +0100 5615802 http://www.medworm.com/index.php?rid=5615801&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F3%2F228%3Frss%3D1 Interest in self-rated health (SRH) as a tool for use in disease and mortality risk screening is increasing. The authors assessed the discriminatory ability of baseline SRH to predict 10-year mortality rates compared with objectively measured health status. Principal component analysis was used to create a health score that included systolic blood pressure, presence of diabetes mellitus, body mass index, electrocardiographic parameters, B-type natriuretic peptide, and other biochemical and hematologic measures. From 1997 to 2007, a total of 474 of the 1,388 baseline participants died and 81 were lost to follow-up, yielding 11,833 person-years of observation. The adjusted hazard ratio for death was 1.74 (95% confidence interval (CI): 1.32, 2.29) for persons reporting poor health versus thos... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5615801 Wed, 18 Jan 2012 05:00:00 +0100 5615801 http://www.medworm.com/index.php?rid=5615800&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F3%2F218%3Frss%3D1 From March to July of 2011, the authors investigated the prospective association between illicit drug use and cognitive functioning during the midadult years. A total of 8,992 participants who were surveyed at 42 years of age in the National Child Development Study (1999–2000) were included. The authors analyzed data on 3 cognitive functioning measures (memory index, executive functioning index, and overall cognitive index) when the participants were 50 years of age (2008–2009). Illicit drug use at 42 years of age was based on self-reported current or past use of any of 12 illicit drugs. Multivariable regression analyses were performed to estimate the association between different illicit drug use measures at 42 years of age and cognitive functioning at 50 years of age. A posit... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5615800 Wed, 18 Jan 2012 05:00:00 +0100 5615800 http://www.medworm.com/index.php?rid=5615799&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F3%2F210%3Frss%3D1 Although missing outcome data are an important problem in randomized trials and observational studies, methods to address this issue can be difficult to apply. Using simulated data, the authors compared 3 methods to handle missing outcome data: 1) complete case analysis; 2) single imputation; and 3) multiple imputation (all 3 with and without covariate adjustment). Simulated scenarios focused on continuous or dichotomous missing outcome data from randomized trials or observational studies. When outcomes were missing at random, single and multiple imputations yielded unbiased estimates after covariate adjustment. Estimates obtained by complete case analysis with covariate adjustment were unbiased as well, with coverage close to 95%. When outcome data were missing not at random, all methods ... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5615799 Wed, 18 Jan 2012 05:00:00 +0100 5615799 http://www.medworm.com/index.php?rid=5615798&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F3%2F208%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5615798 Wed, 18 Jan 2012 05:00:00 +0100 5615798 http://www.medworm.com/index.php?rid=5615797&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F3%2F203%3Frss%3D1 One goal in the post-genome-wide association study era is characterizing gene-environment interactions, including scanning for interactions with all available polymorphisms, not just those showing significant main effects. In recent years, several approaches to such "gene-environment-wide interaction studies" have been proposed. Two contributions in this issue of the American Journal of Epidemiology provide systematic comparisons of the performance of these various approaches, one based on simulation and one based on application to 2 real genome-wide association study scans for type 2 diabetes. The authors discuss some of the broader issues raised by these contributions, including the plausibility of the gene-environment independence assumption that some of these approaches rely upon, the ... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5615797 Wed, 18 Jan 2012 05:00:00 +0100 5615797 http://www.medworm.com/index.php?rid=5615796&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F3%2F191%3Frss%3D1 The question of which statistical approach is the most effective for investigating gene-environment (G-E) interactions in the context of genome-wide association studies (GWAS) remains unresolved. By using 2 case-control GWAS (the Nurses’ Health Study, 1976–2006, and the Health Professionals Follow-up Study, 1986–2006) of type 2 diabetes, the authors compared 5 tests for interactions: standard logistic regression-based case-control; case-only; semiparametric maximum-likelihood estimation of an empirical-Bayes shrinkage estimator; and 2-stage tests. The authors also compared 2 joint tests of genetic main effects and G-E interaction. Elevated body mass index was the exposure of interest and was modeled as a binary trait to avoid an inflated type I error rate that the authors... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5615796 Wed, 18 Jan 2012 05:00:00 +0100 5615796 http://www.medworm.com/index.php?rid=5615795&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F3%2F177%3Frss%3D1 In this report, the authors present a comparative simulation study of power and type I error properties of 3 classes of procedures: 1) the standard 1-step case-control method; 2) the case-only method that requires an assumption of gene-environment independence for the underlying population; and 3) a variety of hybrid methods, including empirical-Bayes, 2-step, and model averaging, that aim at gaining power by exploiting the assumption of gene-environment independence and yet can protect against false positives when the independence assumption is violated. These studies suggest that, although the case-only method generally has maximum power, it has the potential to create substantial false positives in large-scale studies even when a small fraction of markers are associated with the exposur... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5615795 Wed, 18 Jan 2012 05:00:00 +0100 5615795 http://www.medworm.com/index.php?rid=5615794&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F3%2F167%3Frss%3D1 Despite the growing burden of chronic disease globally, few studies have examined the socioeconomic patterning of risk across countries. The authors examined differences in the social patterning of body mass index (BMI) and current smoking by urbanicity among 70 countries from the 2002–2003 World Health Surveys. Age-adjusted, gender-stratified ordinary least squares and logistic regression analyses were conducted in each country to assess the relation between education and BMI or smoking. Meta-analytic techniques were used to assess heterogeneity between countries in the education-risk factor relations. Meta-regression was used to determine whether the heterogeneity could be explained by country-level urbanicity. In the least urban countries, persons with higher education had a highe... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5615794 Wed, 18 Jan 2012 05:00:00 +0100 5615794 http://www.medworm.com/index.php?rid=5615793&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F3%2F159%3Frss%3D1 Legg-Calvé-Perthes’ disease (Perthes’ disease) is a childhood osteonecrosis of the hip for which the disease determinants are poorly understood. In this review, the authors identify studies of Perthes’ disease incidence published up to December 2010 and make denominator populations comparable in order to allow meaningful between-study evaluation. Incidence rates and confidence intervals were determined, and, where appropriate, denominator populations were obtained from national statistical offices. Poisson regression was used to determine the influence of race and geography. The review included 21 studies that described 27 populations in 16 countries, with 124 million person-years of observation. The annual incidence among children under age 15 years ranged from 0.... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5615793 Wed, 18 Jan 2012 05:00:00 +0100 5615793 http://www.medworm.com/index.php?rid=5615792&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F3%2FNP-c%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5615792 Wed, 18 Jan 2012 05:00:00 +0100 5615792 http://www.medworm.com/index.php?rid=5615791&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F3%2FNP-b%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5615791 Wed, 18 Jan 2012 05:00:00 +0100 5615791 http://www.medworm.com/index.php?rid=5615790&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F3%2FNP-a%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5615790 Wed, 18 Jan 2012 05:00:00 +0100 5615790 http://www.medworm.com/index.php?rid=5615789&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F3%2FNP%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5615789 Wed, 18 Jan 2012 05:00:00 +0100 5615789 http://www.medworm.com/index.php?rid=5567362&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2F156-a%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567362 Mon, 02 Jan 2012 05:00:00 +0100 5567362 http://www.medworm.com/index.php?rid=5567361&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2F156%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567361 Mon, 02 Jan 2012 05:00:00 +0100 5567361 http://www.medworm.com/index.php?rid=5567360&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2F154%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567360 Mon, 02 Jan 2012 05:00:00 +0100 5567360 http://www.medworm.com/index.php?rid=5567359&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2F144%3Frss%3D1 The authors investigated whether early-life residency in certain areas of Iceland marked by distinct differences in milk intake was associated with risk of prostate cancer in a population-based cohort of 8,894 men born between 1907 and 1935. Through linkage to cancer and mortality registers, the men were followed for prostate cancer diagnosis and mortality from study entry (in waves from 1967 to 1987) through 2009. In 2002–2006, a subgroup of 2,268 participants reported their milk intake in early, mid-, and current life. During a mean follow-up period of 24.3 years, 1,123 men were diagnosed with prostate cancer, including 371 with advanced disease (stage 3 or higher or prostate cancer death). Compared with early-life residency in the capital area, rural residency in the first 20 year... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567359 Mon, 02 Jan 2012 05:00:00 +0100 5567359 http://www.medworm.com/index.php?rid=5567358&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2F133%3Frss%3D1 Few prospective studies have assessed the incidence and determinants of asymptomatic hyperuricemia in free-living populations. The authors’ goals in this study were to estimate the incidence of hyperuricemia and quantify the dose-response relations of specific risk factors with hyperuricemia in middle-aged South Korean male workers. The authors followed a cohort of 10,802 hyperuricemia-free men aged 30–59 years, examining them annually or biennially at a university hospital in Seoul, South Korea, from 2002 to 2009. A parametric Cox model and a pooled logistic regression model were used to estimate adjusted hazard ratios for incident hyperuricemia (defined as serum uric acid level ≥7.0 mg/dL) according to prespecified risk factors. During 51,210.6 person-years of follow-up, 2... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567358 Mon, 02 Jan 2012 05:00:00 +0100 5567358 http://www.medworm.com/index.php?rid=5567357&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2F131%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567357 Mon, 02 Jan 2012 05:00:00 +0100 5567357 http://www.medworm.com/index.php?rid=5567356&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2F127%3Frss%3D1 Recently, there has been interest in determining whether diet is associated with the risk of venous thromboembolism. The article by Varraso et al. (Am J Epidemiol. 2012;175(2):114–126) published in this issue of the Journal is an important contribution to this literature. In this commentary, the author discusses the findings of Varraso et al. within the context of the existing literature and posits epidemiologic explanations for why investigators might have failed to identify strong associations between diet and venous thromboembolism. (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567356 Mon, 02 Jan 2012 05:00:00 +0100 5567356 http://www.medworm.com/index.php?rid=5567355&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2F114%3Frss%3D1 The authors investigated diet as a risk factor for the development of venous thromboembolism (VTE) among 129,430 US women and men in the Nurses’ Health Study and Health Professionals Follow-up Study. There were 2,892 cases of VTE from 1984 through 2008. Information on participants’ dietary intakes was collected every 2–4 years using a food frequency questionnaire. Dietary patterns (prudent vs. Western), food intakes (fruit, vegetables, fish, red and processed meats, and alcohol), and nutrient intakes (omega-3 fatty acids, trans fatty acids, total fiber, and vitamins K1, B6, B12, and E) were categorized into quintiles, and the risk of VTE was compared among quintiles with the use of Cox proportional hazard models. After adjusting the results for 17 potential confounders, t... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567355 Mon, 02 Jan 2012 05:00:00 +0100 5567355 http://www.medworm.com/index.php?rid=5567354&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2F113%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567354 Mon, 02 Jan 2012 05:00:00 +0100 5567354 http://www.medworm.com/index.php?rid=5567353&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2F111%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567353 Mon, 02 Jan 2012 05:00:00 +0100 5567353 http://www.medworm.com/index.php?rid=5567352&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2F108%3Frss%3D1 In this issue of the Journal, two different articles present epidemiologic evidence supporting the hypotheses that environmental exposures to particulate air pollution or higher temperatures modestly increase the risk of preterm birth. In this commentary, the author discusses environmental epidemiologic methods through the lens of these two papers with respect to the causal question, measurements, and quantification and interpretation of the evidence. Both groups of investigators present results from exploratory analyses that are at the hypothesis-generating end of the research spectrum as opposed to the confirmatory end. The present author describes in qualitative terms a method for decomposing evidence about the association of environmental exposures with prematurity into components repr... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567352 Mon, 02 Jan 2012 05:00:00 +0100 5567352 http://www.medworm.com/index.php?rid=5567351&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2F99%3Frss%3D1 Almost 10% of all births are preterm, and 2.2% are stillbirths. Recent research has suggested that environmental factors may be a contributory cause of these adverse birth outcomes. The authors examined the relation between ambient temperature and preterm birth and stillbirth in Brisbane, Australia, between 2005 and 2009 (n = 101,870). They used a Cox proportional hazards model with livebirth and stillbirth as competing risks. They also examined whether there were periods in pregnancy where exposure to high temperatures had a greater effect. Higher ambient temperatures in the last 4 weeks of the pregnancy increased the risk of stillbirth. The hazard ratio for stillbirth was 0.3 at 12°C relative to the reference temperature of 21°C. The temperature effect was greatest at less than 3... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567351 Mon, 02 Jan 2012 05:00:00 +0100 5567351 http://www.medworm.com/index.php?rid=5567350&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2F91%3Frss%3D1 Exposure to air pollution during pregnancy has been suggested to be a risk factor for preterm birth; however, epidemiologic evidence remains mixed and limited. The authors examined the association between ambient levels of particulate matter <2.5 μm in aerodynamic diameter (PM2.5) and the risk of preterm birth in North Carolina during the period 2001–2005. They estimated the risks of cumulative and lagged average exposures to PM2.5 during pregnancy via a 2-stage discrete-time survival model. The authors also considered exposure metrics derived from 1) ambient concentrations measured by the Air Quality System (AQS) monitoring network and 2) concentrations predicted by statistically fusing AQS data with process-based numerical model output (the Statistically Fused Air and Deposit... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567350 Mon, 02 Jan 2012 05:00:00 +0100 5567350 http://www.medworm.com/index.php?rid=5567349&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2F89%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567349 Mon, 02 Jan 2012 05:00:00 +0100 5567349 http://www.medworm.com/index.php?rid=5567348&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2FNP-c%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567348 Mon, 02 Jan 2012 05:00:00 +0100 5567348 http://www.medworm.com/index.php?rid=5567347&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2FNP-b%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567347 Mon, 02 Jan 2012 05:00:00 +0100 5567347 http://www.medworm.com/index.php?rid=5567346&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2FNP-a%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567346 Mon, 02 Jan 2012 05:00:00 +0100 5567346 http://www.medworm.com/index.php?rid=5567345&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F2%2FNP%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5567345 Mon, 02 Jan 2012 05:00:00 +0100 5567345 http://www.medworm.com/index.php?rid=5531529&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2F86-a%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531529 Wed, 21 Dec 2011 05:00:00 +0100 5531529 http://www.medworm.com/index.php?rid=5531528&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2F86%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531528 Wed, 21 Dec 2011 05:00:00 +0100 5531528 http://www.medworm.com/index.php?rid=5531527&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2F85%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531527 Wed, 21 Dec 2011 05:00:00 +0100 5531527 http://www.medworm.com/index.php?rid=5531526&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2F84%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531526 Wed, 21 Dec 2011 05:00:00 +0100 5531526 http://www.medworm.com/index.php?rid=5531525&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2F74%3Frss%3D1 Changes in women’s menstrual bleeding patterns precede the onset of menopause. In this paper, the authors identify population subgroups based on menstrual characteristics of the menopausal transition experience. Using the TREMIN data set (1943–1979), the authors apply a Bayesian change-point model with 8 parameters for each woman that summarize change in menstrual bleeding patterns during the menopausal transition. The authors then use estimates from this model to classify menstrual patterns into subgroups using a K-medoids algorithm. They identify 6 subgroups of women whose transition experience can be distinguished by age at onset, variability of the menstrual cycle, and duration of the early transition. These results suggest that for most women, mean and variance change poin... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531525 Wed, 21 Dec 2011 05:00:00 +0100 5531525 http://www.medworm.com/index.php?rid=5531524&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2F66%3Frss%3D1 Two methods for point and interval estimation of relative risk for log-linear exposure-response relations in meta-analyses of published ordinal categorical exposure-response data have been proposed. The authors compared the results of a meta-analysis of published data using each of the 2 methods with the results that would be obtained if the primary data were available and investigated the circumstances under which the approximations required for valid use of each meta-analytic method break down. They then extended the methods to handle nonlinear exposure-response relations. In the present article, methods are illustrated using studies of the relation between alcohol consumption and colorectal and lung cancer risks from the ongoing Pooling Project of Prospective Studies of Diet and Cancer.... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531524 Wed, 21 Dec 2011 05:00:00 +0100 5531524 http://www.medworm.com/index.php?rid=5531523&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2F60%3Frss%3D1 Instrumental variable (IV) and risk adjustment (RA) estimators, including propensity score adjustments, are both used to alleviate confounding problems in nonexperimental studies on treatment effects, but it is not clear how estimates based on these 2 approaches compare. Methodological considerations have shown that IV and RA estimators yield estimates of distinct types of causal treatment effects regardless of confounding problems. Many investigators have neglected these distinctions. In this paper, the authors use 3 schematic models to explain visually the relations between IV and RA estimates of intended treatment effects as demonstrated in the methodological studies. When treatment effects are homogeneous across a study population or when treatment effects are heterogeneous across the ... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531523 Wed, 21 Dec 2011 05:00:00 +0100 5531523 http://www.medworm.com/index.php?rid=5531522&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2F54%3Frss%3D1 Helicobacter pylori seroprevalence levels in US adults participating in the continuous National Health and Nutrition Examination Survey (1999–2000) increased with age in all racial/ethnic groups, with significantly higher age-standardized levels in Mexican Americans (64.0%, 95% confidence interval (CI): 58.8, 69.2) and non-Hispanic blacks (52.0%, 95% CI: 48.3, 55.7) compared with non-Hispanic whites (21.2%, 95% CI: 19.1, 23.2). Although seroprevalence levels remained similar to those found in National Health and Nutrition Examination Surveys from 1988 to 1991 among non-Hispanic blacks and Mexican Americans, they were significantly lower in non-Hispanic whites, especially at older ages. The factors driving the decline in H. pylori seroprevalence appear to be acting preferentially on t... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531522 Wed, 21 Dec 2011 05:00:00 +0100 5531522 http://www.medworm.com/index.php?rid=5531521&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2F43%3Frss%3D1 The association between parental smoking and risk of childhood acute lymphoblastic leukemia (ALL) was investigated in an Australian population-based case-control study that included 388 cases and 868 controls aged <15 years, recruited from 2003 to 2006. Both of the child’s parents provided information about their smoking habits for each year from age 15 years to the child’s birth. Data were analyzed by logistic regression. Maternal smoking was not associated with risk of childhood ALL, but the odds ratio for paternal smoking of ≥15 cigarettes per day around the time of the child’s conception was 1.35 (95% confidence interval: 0.98, 1.86). The associations between parental smoking risk of childhood ALL did not differ substantially by immunophenotypic or cytogenetic s... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531521 Wed, 21 Dec 2011 05:00:00 +0100 5531521 http://www.medworm.com/index.php?rid=5531520&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2F33%3Frss%3D1 Data from the 1958 National Child Development Study (1958–2004) were used in a prospective study of the relation of financial adversity in childhood to lung function in midlife. It was hypothesized that such a relation would be found and would be mediated partly by early housing deprivation, partly by continuities in social disadvantage, and partly by smoking. These hypotheses were confirmed. The mediating variables explained nearly two-thirds of the observed relation. The strongest individual pathway from early financial hardship to adult lung function was through poor housing in childhood. Poor housing increased the risk of educational failure, which in turn was strongly related to less-advantaged social class. Lack of educational qualifications and less-advantaged social class ind... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531520 Wed, 21 Dec 2011 05:00:00 +0100 5531520 http://www.medworm.com/index.php?rid=5531519&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2F22%3Frss%3D1 In randomized trials, the effect of vitamin D supplementation on blood pressure has been equivocal, while most prospective cohort studies have shown that the risk of incident hypertension is lower in people with higher levels of 25-hydroxyvitamin D (25(OH)D). The authors examined the association between levels of 25(OH)D and changes in blood pressure and incident hypertension in 4,863 postmenopausal women recruited into the Women’s Health Initiative between 1993 and 1998. Over 7 years, there were no significant differences in the adjusted mean change in systolic or diastolic blood pressure by quartile of 25(OH)D. The covariate-adjusted risk of incident hypertension was slightly lower in the upper 3 quartiles of 25(OH)D compared with the lowest quartile, but this was statistically sig... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531519 Wed, 21 Dec 2011 05:00:00 +0100 5531519 http://www.medworm.com/index.php?rid=5531518&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2F11%3Frss%3D1 The World Health Organization estimates that the number of obese and overweight adults has increased to 1.6 billion, with concomitant increases in comorbidity. While genetic factors for obesity have been extensively studied in Caucasians, fewer studies have investigated genetic determinants of body mass index (BMI; weight (kg)/height (m)2) in African Americans. A total of 38 genes and 1,086 single nucleotide polymorphisms (SNPs) in African Americans (n = 1,173) and 897 SNPs in Caucasians (n = 1,165) were examined in the Southern Community Cohort Study (2002–2009) for associations with BMI and gene x environment interactions. A statistically significant association with BMI survived correction for multiple testing at rs4140535 (β = –0.04, 95% confidence interval: –0.0... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531518 Wed, 21 Dec 2011 05:00:00 +0100 5531518 http://www.medworm.com/index.php?rid=5531517&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2F1%3Frss%3D1 To comprehensively evaluate the impact of recently identified colorectal cancer (CRC) variants at 1q41, 3q26.2, 8q23.3, 8q24.21, 10p14, 11q23.1, 12q13.13, 14q22.2, 15q13.3, 16q22.1, 18q21.1, 19q13.11, 20p12.3, and 20q13.33 on risk and CRC phenotype, the authors analyzed 8,878 cases and 6,051 controls from the United Kingdom ascertained in 1999–2007. The impact of variants on the familial CRC risk was enumerated from age-, sex-, and calendar-specific CRC rates in the 50,924 first-degree relatives of cases. Each of the 14 susceptibility loci independently influences CRC with the risk increasing with increasing number of risk alleles carried (per allele odds ratio = 1.13; P = 2.99 x 10–58) and, for those within the upper quintile, there is a 2.3-fold increased risk. In first-degre... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531517 Wed, 21 Dec 2011 05:00:00 +0100 5531517 http://www.medworm.com/index.php?rid=5531516&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2FNP-c%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531516 Wed, 21 Dec 2011 05:00:00 +0100 5531516 http://www.medworm.com/index.php?rid=5531515&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2FNP-b%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531515 Wed, 21 Dec 2011 05:00:00 +0100 5531515 http://www.medworm.com/index.php?rid=5531514&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2FNP-a%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531514 Wed, 21 Dec 2011 05:00:00 +0100 5531514 http://www.medworm.com/index.php?rid=5531513&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F175%2F1%2FNP%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5531513 Wed, 21 Dec 2011 05:00:00 +0100 5531513 http://www.medworm.com/index.php?rid=5500005&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1425%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5500005 Mon, 12 Dec 2011 05:00:00 +0100 5500005 http://www.medworm.com/index.php?rid=5500004&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1424%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5500004 Mon, 12 Dec 2011 05:00:00 +0100 5500004 http://www.medworm.com/index.php?rid=5500003&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1423-a%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5500003 Mon, 12 Dec 2011 05:00:00 +0100 5500003 http://www.medworm.com/index.php?rid=5500002&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1423%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5500002 Mon, 12 Dec 2011 05:00:00 +0100 5500002 http://www.medworm.com/index.php?rid=5500001&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1416%3Frss%3D1 Lagging exposure information is often undertaken to allow for a latency period in cumulative exposure-disease analyses. The authors first consider bias and confidence interval coverage when using the standard approaches of fitting models under several lag assumptions and selecting the lag that maximizes either the effect estimate or model goodness of fit. Next, they consider bias that occurs when the assumption that the latency period is a fixed constant does not hold. Expressions were derived for bias due to misspecification of lag assumptions, and simulations were conducted. Finally, the authors describe a method for joint estimation of parameters describing an exposure-response association and the latency distribution. Analyses of associations between cumulative asbestos exposure and lu... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5500001 Mon, 12 Dec 2011 05:00:00 +0100 5500001 http://www.medworm.com/index.php?rid=5500000&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1406%3Frss%3D1 The authors aimed to describe how longitudinal patterns of physical activity during mid-adulthood (ages 31–53 years) can be characterized using latent class analysis in a population-based birth cohort study, the Medical Research Council’s 1946 National Survey of Health and Development. Three different types of physical activity—walking, cycling, and leisure-time physical activity—were analyzed separately using self-reported data collected from questionnaires between 1977 and 1999; 3,847 study members were included in the analysis for one or more types of activity. Patterns of activity differed by sex, so stratified analyses were conducted. Two walking latent classes were identified representing low (52.8% of males in the cohort, 33.5% of females) and high (47.2%, 66... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5500000 Mon, 12 Dec 2011 05:00:00 +0100 5500000 http://www.medworm.com/index.php?rid=5499999&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1396%3Frss%3D1 Since the year 2000, evaluation of the impact of air pollution on people's health has drawn the attention of the general public and has led decision-makers to develop specific health policies. In most of the health impact assessment literature, investigators have reported on long- and short-term effects of air pollution. Here the authors present results of a health impact assessment of short-term effects of particulate matter ≤10 μm in diameter (PM10) in the Lombardy region of Italy (2003–2006). The impact was evaluated in terms of numbers of attributable deaths under several counterfactual scenarios of air pollution reduction based on World Health Organization guidelines and European Union limits. The authors found that annual average PM10 levels exceeding the World Health Org... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499999 Mon, 12 Dec 2011 05:00:00 +0100 5499999 http://www.medworm.com/index.php?rid=5499998&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1391%3Frss%3D1 Five novel prostate cancer risk loci were identified in a recent genome-wide association study (GWAS) of Japanese persons (Takata et al., Nat Genet. 2010;42(9):751–754). Those authors proposed that apart from population-specific linkage disequilibrium patterns, limitations of GWAS single nucleotide polymorphism (SNP) prioritization and/or study design could explain the lack of identification of these loci in GWAS previously conducted among Caucasians. Thus, the authors undertook a replication study in 1,357 prostate cancer patients and 1,403 healthy Australian males of European descent (2004–2008). The rs12653946 SNP at 5p15 was found to be significantly associated with prostate cancer risk (odds ratio = 1.20, 95% confidence interval: 1.07, 1.34; P = 0.002). On the basis of lin... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499998 Mon, 12 Dec 2011 05:00:00 +0100 5499998 http://www.medworm.com/index.php?rid=5499997&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1382%3Frss%3D1 Earlier studies suggest a protective association between vitamin K antagonist (VKA) anticoagulants and the incidence of cancer. The authors examined the associations between VKA therapy and incidence of 24 site-specific cancers with a Danish population-based cohort study, using heart valve replacement as an instrumental variable. The authors enrolled 9,727 Danish residents who received a replacement heart valve between 1989 and 2006. The heart valve recipients were matched with 95,481 unexposed individuals on age and sex. The authors used the heart valve replacement instrument to estimate rate ratios associating VKA therapy with incidence of the 24 site-specific cancers using Poisson regression models. Direct associations between VKA therapy and incidence of the 24 cancers were estimated i... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499997 Mon, 12 Dec 2011 05:00:00 +0100 5499997 http://www.medworm.com/index.php?rid=5499996&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1373%3Frss%3D1 Patient vital status generally is passively obtained by cancer registries, and no previous population-based studies have used extensive active follow-up to compute a more accurate overall survival rate for pancreatic cancer. Therefore, the authors used multiple active and passive follow-up methods to determine vital status and date of death for 1,954 pancreatic cancer patients diagnosed from 1995 to 1999 in a large population-based study in the San Francisco Bay Area, California. Survival rates were estimated by using Kaplan-Meier methods. Hazard ratios and 95% confidence intervals were estimated by using multivariable Cox proportional-hazards models. Vital status was confirmed for >99% of 1,954 patients. The overall 5-year survival rate was 1.3% and was greater in patients who were you... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499996 Mon, 12 Dec 2011 05:00:00 +0100 5499996 http://www.medworm.com/index.php?rid=5499995&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1363%3Frss%3D1 In conclusion, serum 25(OH)D varies in a sinusoidal manner, with large seasonal differences relative to mean concentration and laboratory evidence of biologic sequelae. Single 25(OH)D measurements might not capture overall vitamin D status, and the extent of misclassification could vary by demographic and behavioral factors. Accounting for collection time may reduce bias in research studies and improve decision-making in clinical care. (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499995 Mon, 12 Dec 2011 05:00:00 +0100 5499995 http://www.medworm.com/index.php?rid=5499994&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1354%3Frss%3D1 This article examines whether direct exposure to work-related violence is associated with clinically pertinent mental health problems, measured by purchases of psychotropics (antidepressants, anxiolytics, hypnotics), in a cross-occupational sample of 15,246 Danish employees free from using psychotropics at baseline. Self-reported data on work-related violence were merged with other data on purchases of medications through a national registry to estimate cause-specific hazard ratios during 3.6 years (1,325 days) of follow-up in the years 1996–2008. Outcomes were examined as competing risks, and analyses were adjusted for gender, age, cohabitation, education, income, social support from colleagues, social support from supervisor, and influence and quantitative demands at work. Work-rel... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499994 Mon, 12 Dec 2011 05:00:00 +0100 5499994 http://www.medworm.com/index.php?rid=5499993&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1345%3Frss%3D1 Pessimism, a general tendency toward negative expectancies, is a risk factor for depression and also heart disease, stroke, and reduced cancer survival. There is evidence that individuals with higher lead exposure have poorer health. However, low socioeconomic status (SES) is linked with higher lead levels and greater pessimism, and it is unclear whether lead influences psychological functioning independently of other social factors. The authors considered interrelations among childhood and adult SES, lead levels, and psychological functioning in data collected on 412 Boston area men between 1991 and 2002 in a subgroup of the VA Normative Aging Study. Pessimism was measured by using the Life Orientation Test. Cumulative (tibia) lead was measured by x-ray fluorescence. Structural equation m... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499993 Mon, 12 Dec 2011 05:00:00 +0100 5499993 http://www.medworm.com/index.php?rid=5499992&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1336%3Frss%3D1 The study reports on the associations of infant and childhood anthropometric measurements, early growth, and the combined effect of birth weight and childhood body mass index with older age physical functioning among 1,999 individuals born in 1934–1944 and belonging to the Helsinki Birth Cohort Study. Physical functioning was assessed by the Short Form 36 scale. Anthropometric data from infancy and childhood were retrieved from medical records. The risk of lower Short Form 36 physical functioning at the mean age of 61.6 years was increased for those with birth weight less than 2.5 kg compared with those weighing 3.0–3.5 kg at birth (odds ratio (OR) = 2.73, 95% confidence interval (CI): 1.57, 4.72). The gain in weight from birth to age 2 years was associated with decreased risk ... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499992 Mon, 12 Dec 2011 05:00:00 +0100 5499992 http://www.medworm.com/index.php?rid=5499991&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1335%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499991 Mon, 12 Dec 2011 05:00:00 +0100 5499991 http://www.medworm.com/index.php?rid=5499990&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1332%3Frss%3D1 The typical dilemma with sex-ratio findings is that when they are real, they aren’t interesting, and when they are interesting, they aren’t real. In this issue of the Journal, Fernández et al. (Am J Epidemiol. 2011;174(12):1327–1331) describe a deviation of the sex ratio that is apparently both large and real. There was a temporary but distinct spike in the proportion of boys born in Cuba around the time of the collapse of the national economy during the 1990s. Although an excess of boys does not fit the prevailing biologic theory regarding maternal stress and the sex ratio, the data are consistent with results from the Dutch famine (where population-level deprivation was even more extreme). A new quandary arises in the modern era with interpretation of the sex rat... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499990 Mon, 12 Dec 2011 05:00:00 +0100 5499990 http://www.medworm.com/index.php?rid=5499989&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2F1327%3Frss%3D1 The Trivers-Willard hypothesis suggests that populations respond to scarcity by decreasing the ratio of males to females at livebirth. Cuba experienced an extreme economic depression in the 1990s called the "special period." Using time-series analysis, the authors studied the impact of this event on the male:female sex ratio at birth in Cuba from 1960 to 2008. From 1990 to 1993, the per capita gross domestic product in Cuba decreased by 36%. By use of a definition of the special period from 1991 to 1998, there was a prolonged increase in the male:female ratio of livebirths during this period of economic depression (P < 0.001), from 1.06 at baseline to a peak of 1.18. This association persisted when using alternative definitions of the duration of economic depression in sensitivity analy... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499989 Mon, 12 Dec 2011 05:00:00 +0100 5499989 http://www.medworm.com/index.php?rid=5499988&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2FNP-c%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499988 Mon, 12 Dec 2011 05:00:00 +0100 5499988 http://www.medworm.com/index.php?rid=5499987&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2FNP-b%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499987 Mon, 12 Dec 2011 05:00:00 +0100 5499987 http://www.medworm.com/index.php?rid=5499986&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2FNP-a%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499986 Mon, 12 Dec 2011 05:00:00 +0100 5499986 http://www.medworm.com/index.php?rid=5499985&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2FNP%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499985 Mon, 12 Dec 2011 05:00:00 +0100 5499985 http://www.medworm.com/index.php?rid=5499984&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F12%2FNA%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5499984 Mon, 12 Dec 2011 05:00:00 +0100 5499984 http://www.medworm.com/index.php?rid=5453340&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1324%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453340 Fri, 25 Nov 2011 05:00:00 +0100 5453340 http://www.medworm.com/index.php?rid=5453339&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1323%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453339 Fri, 25 Nov 2011 05:00:00 +0100 5453339 http://www.medworm.com/index.php?rid=5453338&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1316%3Frss%3D1 Common polymorphisms in the N-acetyltransferase 2 gene (NAT2) modify the association between cigarette smoking and bladder cancer and have been hypothesized to determine whether active cigarette smoking increases breast cancer risk. The authors sought to replicate the latter hypothesis in a prospective analysis of 6,900 breast cancer cases and 9,903 matched controls drawn from 6 cohorts (1989–2006) in the National Cancer Institute’s Breast and Prostate Cancer Cohort Consortium. Standardized methods were used to genotype the 3 most common polymorphisms that define NAT2 acetylation phenotype (rs1799930, rs1799931, and rs1801280). In unconditional logistic regression analyses, breast cancer risk was higher in women with more than 20 pack-years of active cigarette smoking than in n... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453338 Fri, 25 Nov 2011 05:00:00 +0100 5453338 http://www.medworm.com/index.php?rid=5453337&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1307%3Frss%3D1 Despite considerable research efforts in specific subpopulations, reliable estimates of the infection attack rates and severity of 2009 influenza A (H1N1) in the general population remain scarce. Such estimates are essential to the tailoring of future control strategies. Therefore, 2 serial population-based serologic surveys were conducted, before and after the 2009 influenza A (H1N1) epidemic, in the Netherlands. Random age-stratified samples were obtained using a 2-stage cluster design. Participants donated blood and completed a questionnaire. Data on sentinel general practitioner-attended influenza-like illness and nationwide hospitalization and mortality were used to assess the severity of infection. The estimated infection attack rates were low in the general population (7.6%, 95% con... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453337 Fri, 25 Nov 2011 05:00:00 +0100 5453337 http://www.medworm.com/index.php?rid=5453336&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1296%3Frss%3D1 Greening of vacant urban land may affect health and safety. The authors conducted a decade-long difference-in-differences analysis of the impact of a vacant lot greening program in Philadelphia, Pennsylvania, on health and safety outcomes. "Before" and "after" outcome differences among treated vacant lots were compared with matched groups of control vacant lots that were eligible but did not receive treatment. Control lots from 2 eligibility pools were randomly selected and matched to treated lots at a 3:1 ratio by city section. Random-effects regression models were fitted, along with alternative models and robustness checks. Across 4 sections of Philadelphia, 4,436 vacant lots totaling over 7.8 million square feet (about 725,000 m2) were greened from 1999 to 2008. Regression-adjusted esti... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453336 Fri, 25 Nov 2011 05:00:00 +0100 5453336 http://www.medworm.com/index.php?rid=5453335&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1286%3Frss%3D1 Nitrosatable drugs, such as secondary or tertiary amines and amides, form N-nitroso compounds in the presence of nitrite. Various N-nitroso compounds have been associated with neural tube defects in animal models. Using data from the National Birth Defects Prevention Study, the authors examined nitrosatable drug exposure 1 month before and 1 month after conception in 1,223 case mothers with neural tube defect-affected pregnancies and 6,807 control mothers who delivered babies without major congenital anomalies from 1997 to 2005. Nitrite intakes were estimated from mothers’ responses to a food frequency questionnaire. After adjustment for maternal race/ethnicity, educational level, and folic acid supplementation, case women were more likely than were control women to have taken tertia... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453335 Fri, 25 Nov 2011 05:00:00 +0100 5453335 http://www.medworm.com/index.php?rid=5453334&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1275%3Frss%3D1 In conclusion, children delivered by cesarean section may have an increased risk of current asthma at 36 months, but residual confounding cannot be excluded. In future prospective studies, investigators should reexamine this association in different age groups. (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453334 Fri, 25 Nov 2011 05:00:00 +0100 5453334 http://www.medworm.com/index.php?rid=5453333&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1266%3Frss%3D1 The psychometric properties of instruments used to measure self-reported experiences of discrimination in epidemiologic studies are rarely assessed, especially regarding construct validity. The authors used 2000–2001 data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study to examine differential item functioning (DIF) in 2 versions of the Experiences of Discrimination (EOD) Index, an index measuring self-reported experiences of racial/ethnic and gender discrimination. DIF may confound interpretation of subgroup differences. Large DIF was observed for 2 of 7 racial/ethnic discrimination items: White participants reported more racial/ethnic discrimination for the "at school" item, and black participants reported more racial/ethnic discrimination for the "getting h... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453333 Fri, 25 Nov 2011 05:00:00 +0100 5453333 http://www.medworm.com/index.php?rid=5453332&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1256%3Frss%3D1 To date, Web-based 24-hour recalls have not been validated using objective biomarkers. From 2006 to 2009, the validity of 6 Web-based DietDay 24-hour recalls was tested among 115 black and 118 white healthy adults from Los Angeles, California, by using the doubly labeled water method, and the results were compared with the results of the Diet History Questionnaire, a food frequency questionnaire developed by the National Cancer Institute. The authors performed repeated measurements in a subset of 53 subjects approximately 6 months later to estimate the stability of the doubly labeled water measurement. The attenuation factors for the DietDay recall were 0.30 for blacks and 0.26 for whites. For the Diet History Questionnaire, the attenuation factors were 0.15 and 0.17 for blacks and whites,... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453332 Fri, 25 Nov 2011 05:00:00 +0100 5453332 http://www.medworm.com/index.php?rid=5453331&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1246%3Frss%3D1 A prospective survey of social mixing patterns relevant to respiratory disease transmission by large droplets (e.g., influenza) or small droplet nuclei (e.g., tuberculosis) was performed in a South African township in 2010. A total of 571 randomly selected participants recorded the numbers, times, and locations of close contacts (physical/nonphysical) and indoor casual contacts met daily. The median number of physical contacts was 12 (interquartile range (IQR), 7–18), the median number of close contacts was 20 (IQR, 13–29), and the total number of indoor contacts was 30 (IQR, 12–54). Physical and close contacts were most frequent and age-associative in youths aged 5–19 years. Numbers of close contacts were 40% higher than in corresponding populations in industrializ... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453331 Fri, 25 Nov 2011 05:00:00 +0100 5453331 http://www.medworm.com/index.php?rid=5453330&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1238%3Frss%3D1 The authors describe a statistical method of combining self-reports and biomarkers that, with adequate control for confounding, will provide nearly unbiased estimates of diet-disease associations and a valid test of the null hypothesis of no association. The method is based on regression calibration. In cases in which the diet-disease association is mediated by the biomarker, the association needs to be estimated as the total dietary effect in a mediation model. However, the hypothesis of no association is best tested through a marginal model that includes as the exposure the regression calibration-estimated intake but not the biomarker. The authors illustrate the method with data from the Carotenoids and Age-Related Eye Disease Study (2001--2004) and show that inclusion of the biomarker i... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453330 Fri, 25 Nov 2011 05:00:00 +0100 5453330 http://www.medworm.com/index.php?rid=5453329&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1230%3Frss%3D1 In this article, the authors demonstrate a time-series analysis based on a hierarchical Bayesian model of a Poisson outcome with an excessive number of zeroes. The motivating example for this analysis comes from the intensive care unit (ICU) of an urban university teaching hospital (New Haven, Connecticut, 2002–2004). Studies of medication use among older patients in the ICU are complicated by statistical factors such as an excessive number of zero doses, periodicity, and within-person autocorrelation. Whereas time-series techniques adjust for autocorrelation and periodicity in outcome measurements, Bayesian analysis provides greater precision for small samples and the flexibility to conduct posterior predictive simulations. By applying elements of time-series analysis within both fr... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453329 Fri, 25 Nov 2011 05:00:00 +0100 5453329 http://www.medworm.com/index.php?rid=5453328&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1228%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453328 Fri, 25 Nov 2011 05:00:00 +0100 5453328 http://www.medworm.com/index.php?rid=5453327&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1223%3Frss%3D1 In choosing covariates for adjustment or inclusion in propensity score analysis, researchers must weigh the benefit of reducing confounding bias carried by those covariates against the risk of amplifying residual bias carried by unmeasured confounders. The latter is characteristic of covariates that act like instrumental variables—that is, variables that are more strongly associated with the exposure than with the outcome. In this issue of the Journal (Am J Epidemiol. 2011;174(11):1213–1222), Myers et al. compare the bias amplification of a near-instrumental variable with its bias-reducing potential and suggest that, in practice, the latter outweighs the former. The author of this commentary sheds broader light on this comparison by considering the cumulative effects of conditi... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453327 Fri, 25 Nov 2011 05:00:00 +0100 5453327 http://www.medworm.com/index.php?rid=5453326&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1213%3Frss%3D1 Recent theoretical studies have shown that conditioning on an instrumental variable (IV), a variable that is associated with exposure but not associated with outcome except through exposure, can increase both bias and variance of exposure effect estimates. Although these findings have obvious implications in cases of known IVs, their meaning remains unclear in the more common scenario where investigators are uncertain whether a measured covariate meets the criteria for an IV or rather a confounder. The authors present results from two simulation studies designed to provide insight into the problem of conditioning on potential IVs in routine epidemiologic practice. The simulations explored the effects of conditioning on IVs, near-IVs (predictors of exposure that are weakly associated with o... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453326 Fri, 25 Nov 2011 05:00:00 +0100 5453326 http://www.medworm.com/index.php?rid=5453325&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2F1211%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453325 Fri, 25 Nov 2011 05:00:00 +0100 5453325 http://www.medworm.com/index.php?rid=5453324&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2FNP-c%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453324 Fri, 25 Nov 2011 05:00:00 +0100 5453324 http://www.medworm.com/index.php?rid=5453323&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2FNP-b%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453323 Fri, 25 Nov 2011 05:00:00 +0100 5453323 http://www.medworm.com/index.php?rid=5453322&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2FNP-a%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453322 Fri, 25 Nov 2011 05:00:00 +0100 5453322 http://www.medworm.com/index.php?rid=5453321&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F11%2FNP%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5453321 Fri, 25 Nov 2011 05:00:00 +0100 5453321 http://www.medworm.com/index.php?rid=5372576&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2F1204%3Frss%3D1 Dialysis has been used in the treatment of patients with end-stage renal disease since the 1960s. Recently, several large observational studies have been conducted to assess whether early initiation of dialysis prolongs survival, as compared with late initiation. However, these studies have used analytic approaches which are likely to suffer from either lead-time bias or immortal-time bias. In this paper, the authors demonstrate that recently developed methods in the causal inference literature can be used to avoid both types of bias and accurately estimate the ideal time for dialysis initiation from observational data. This is illustrated using data from a nationwide population-based cohort of patients with chronic kidney disease in Sweden (1996–2003). (Source: American Journal of E... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372576 Thu, 03 Nov 2011 04:00:00 +0100 5372576 http://www.medworm.com/index.php?rid=5372575&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2F1197%3Frss%3D1 Estimates of additive interaction from case-control data are often obtained by logistic regression; such models can also be used to adjust for covariates. This approach to estimating additive interaction has come under some criticism because of possible misspecification of the logistic model: If the underlying model is linear, the logistic model will be misspecified. The authors propose an inverse probability of treatment weighting approach to causal effects and additive interaction in case-control studies. Under the assumption of no unmeasured confounding, the approach amounts to fitting a marginal structural linear odds model. The approach allows for the estimation of measures of additive interaction between dichotomous exposures, such as the relative excess risk due to interaction, usin... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372575 Thu, 03 Nov 2011 04:00:00 +0100 5372575 http://www.medworm.com/index.php?rid=5372574&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2F1190%3Frss%3D1 One of the many challenges hindering the global response to the human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) epidemic is the difficulty of collecting reliable information about the populations most at risk for the disease. Thus, the authors empirically assessed a promising new method for estimating the sizes of most at-risk populations: the network scale-up method. Using 4 different data sources, 2 of which were from other researchers, the authors produced 5 estimates of the number of heavy drug users in Curitiba, Brazil. The authors found that the network scale-up and generalized network scale-up estimators produced estimates 5–10 times higher than estimates made using standard methods (the multiplier method and the direct estimation method using data... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372574 Thu, 03 Nov 2011 04:00:00 +0100 5372574 http://www.medworm.com/index.php?rid=5372573&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2F1183%3Frss%3D1 Family-based designs protect analyses of genetic effects from bias that is due to population stratification. Investigators have assumed that this robustness extends to assessments of gene-environment interaction. Unfortunately, this assumption fails for the common scenario in which the genotyped variant is related to risk through linkage with a causative allele. Bias also plagues other methods of assessment of gene-environment interaction. When testing against multiplicative joint effects, the case-only design offers excellent power, but it is invalid if genotype and exposure are correlated in the population. The authors describe 4 mechanisms that produce genotype-exposure dependence: exposure-related genetic population stratification, effects of family history on behavior, genotype effect... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372573 Thu, 03 Nov 2011 04:00:00 +0100 5372573 http://www.medworm.com/index.php?rid=5372572&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2F1175%3Frss%3D1 Because the incidence of human immunodeficiency virus (HIV) infection is difficult to measure directly, prevalence trends often serve to track epidemiologic changes. Adult HIV prevalence in open population cohort studies, however, reflects changes in incidence, population factors (migration, deaths, and aging), and survey coverage. Data from an open cohort in rural Uganda enabled estimation of the contribution of these factors to prevalence trends from 1989 to 2007. New infections within this cohort represented on average 44% of new prevalent cases per year. Other factors affecting changes in prevalence included migration and death. Migrants and mobile people (those who leave and return to the study area) are in a higher-risk group and thus can affect prevalence trends. Incidence of HIV in... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372572 Thu, 03 Nov 2011 04:00:00 +0100 5372572 http://www.medworm.com/index.php?rid=5372571&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2F1166%3Frss%3D1 Studies published in the last 3 decades have demonstrated global human exposure to polybrominated diphenyl ether (PBDE) flame retardants. A growing body of literature suggests that PBDEs may disrupt thyroid hormone homeostasis. Although thyroid hormones play an essential role in brain development, few studies have investigated relations between prenatal exposure to PBDEs and neonatal thyroid hormone levels, and none have measured thyroid-stimulating hormone (TSH) levels in neonates. The authors measured 10 PBDE congeners in serum collected between October 1999 and October 2000 from 289 pregnant women living in California's Salinas Valley and abstracted TSH levels from their children's medical records. Individual PBDE congeners showed null or weak nonsignificant inverse relations with neona... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372571 Thu, 03 Nov 2011 04:00:00 +0100 5372571 http://www.medworm.com/index.php?rid=5372570&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2F1159%3Frss%3D1 There is increasing evidence that in utero effects of excessive gestational weight gain may result in increased weight in children; however, studies have not controlled for shared genetic or environmental factors between mothers and children. Using 2,758 family groups from the Collaborative Perinatal Project, the authors examined the association of maternal prepregnancy body mass index (BMI) and gestational weight gain on child BMI at age 4 years using both conventional generalized estimating equations and fixed-effects models that account for shared familial factors. With generalized estimating equations, prepregnancy BMI and gestational weight gain had similar associations with the child BMI z score (β = 0.09 units, 95% confidence interval (CI): 0.08, 0.11; and β = 0.07 units, ... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372570 Thu, 03 Nov 2011 04:00:00 +0100 5372570 http://www.medworm.com/index.php?rid=5372569&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2F1147%3Frss%3D1 In conclusion, never or curtailed lactation was associated with an increased risk of incident maternal hypertension, compared with the recommended ≥6 months of exclusive or ≥12 months of total lactation per child, in a large cohort of parous women. (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372569 Thu, 03 Nov 2011 04:00:00 +0100 5372569 http://www.medworm.com/index.php?rid=5372568&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2F1140%3Frss%3D1 This study provides, for the first time, precise estimates of sojourn time by age and sex, and it suggests that sojourn times are remarkably consistent across age groups and in both sexes. (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372568 Thu, 03 Nov 2011 04:00:00 +0100 5372568 http://www.medworm.com/index.php?rid=5372567&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2F1127%3Frss%3D1 A large body size may differentially influence risk of colorectal cancer (CRC) by anatomic location. The Netherlands Cohort Study includes 120,852 men and women aged 55–69 years who self-reported weight, height, and trouser/skirt size at baseline (1986), as well as weight at age 20 years. Derived variables included body mass index (BMI; weight (kg)/height (m)2), BMI at age 20 years, and BMI change. After 16.3 years of follow-up (1986–2002), 2,316 CRC cases were available for case-cohort analysis. In men, the highest risk estimates were observed for body fat (per 5-unit increase in BMI, hazard ratio (HR) = 1.25, 95% confidence interval (CI): 1.05, 1.46; for highest quintile of trouser size vs. lowest, HR = 1.63, 95% CI: 1.17, 2.29 (P-trend = 0.02)) and appeared more closely asso... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372567 Thu, 03 Nov 2011 04:00:00 +0100 5372567 http://www.medworm.com/index.php?rid=5372566&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2F1115%3Frss%3D1 Obesity is a well-established risk factor for endometrial cancer, the most common gynecologic malignancy. Recent genome-wide association studies (GWAS) have identified multiple genetic markers for obesity. The authors evaluated the association of obesity-related single nucleotide polymorphisms (SNPs) with endometrial cancer using GWAS data from their recently completed study, the Shanghai Endometrial Cancer Genetics Study, which comprised 832 endometrial cancer cases and 2,049 controls (1996–2005). Thirty-five SNPs previously associated with obesity or body mass index (BMI; weight (kg)/height (m)2) at a minimum significance level of ≤5 x 10–7 in the US National Human Genome Research Institute's GWAS catalog (http://genome.gov/gwastudies) and representing 26 unique loci were ... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372566 Thu, 03 Nov 2011 04:00:00 +0100 5372566 http://www.medworm.com/index.php?rid=5372565&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2F1108%3Frss%3D1 In this study, the authors assessed the relation between BMI and proximity to food establishments over a 30-year period among 3,113 subjects in the Framingham Heart Study Offspring Cohort living in 4 Massachusetts towns during 1971–2001. The authors used novel data that included repeated measures of BMI and accounted for residential mobility and the appearance and disappearance of food establishments. They calculated proximity to food establishments as the driving distance between each subject’s residence and nearby food establishments, divided into 6 categories. The authors used cross-classified linear mixed models to account for time-varying attributes of individuals and residential neighborhoods. Each 1-km increase in distance to the closest fast-food restaurant was associat... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372565 Thu, 03 Nov 2011 04:00:00 +0100 5372565 http://www.medworm.com/index.php?rid=5372564&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2F1101%3Frss%3D1 The ecologic study design is routinely used by epidemiologists in spite of its limitations. It is presently unknown how well the challenges of the design are dealt with in epidemiologic research. The purpose of this bibliometric review was to critically evaluate the characteristics, statistical methods, and reporting of results of modern cross-sectional ecologic papers. A search through 6 major epidemiology journals identified all cross-sectional ecologic studies published since January 1, 2000. A total of 125 articles met the inclusion requirements and were assessed via common evaluative criteria. It was found that a considerable number of cross-sectional ecologic studies use unreliable methods or contain statistical oversights; most investigators who adjusted their outcomes for age or se... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372564 Thu, 03 Nov 2011 04:00:00 +0100 5372564 http://www.medworm.com/index.php?rid=5372563&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2FNP-c%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372563 Thu, 03 Nov 2011 04:00:00 +0100 5372563 http://www.medworm.com/index.php?rid=5372562&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2FNP-b%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372562 Thu, 03 Nov 2011 04:00:00 +0100 5372562 http://www.medworm.com/index.php?rid=5372561&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2FNP-a%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372561 Thu, 03 Nov 2011 04:00:00 +0100 5372561 http://www.medworm.com/index.php?rid=5372560&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F10%2FNP%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5372560 Thu, 03 Nov 2011 04:00:00 +0100 5372560 http://www.medworm.com/index.php?rid=5342333&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2F1089%3Frss%3D1 Selective prescribing of conventional antipsychotic medication (APM) to frailer patients is thought to have led to overestimation of the association with mortality in pharmacoepidemiologic studies relying on claims data. The authors assessed the validity of different analytic techniques to address such confounding. The cohort included 82,012 persons initiating APM use after admission to a nursing home in 45 states with 2001–2005 Medicaid/Medicare data, linked to clinical data (Minimum Data Set) and institutional characteristics. The authors compared the association between APM class and 180-day mortality with multivariate outcome modeling, propensity score (PS) adjustment, and instrumental variables. The unadjusted risk difference (per 100 patients) of 10.6 (95% confidence interval (... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342333 Thu, 20 Oct 2011 04:00:00 +0100 5342333 http://www.medworm.com/index.php?rid=5342332&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2F1077%3Frss%3D1 The linear mixed model (LMM), which is routinely used to describe change in outcomes over time and its association with risk factors, assumes that a unit change in any predictor is associated with a constant change in the outcome. When it is used on psychometric tests, this assumption may not hold. Indeed, psychometric tests usually suffer from ceiling and/or floor effects and curvilinearity (i.e., varying sensitivity to change). The authors aimed to determine the consequences of such misspecification when evaluating predictors of cognitive decline. As an alternative to the LMM, they considered 2 mixed models based on latent processes that handle discrete and bounded outcomes. Model differences are illustrated here using data on 4 psychometric tests from the Personnes Agées QUID (PA... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342332 Thu, 20 Oct 2011 04:00:00 +0100 5342332 http://www.medworm.com/index.php?rid=5342331&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2F1069%3Frss%3D1 Mendelian randomization studies typically have low power. Where there are several valid candidate genetic instruments, precision can be gained by using all the instruments available. However, sporadically missing genetic data can offset this gain. The authors describe 4 Bayesian methods for imputing the missing data based on a missing-at-random assumption: multiple imputations, single nucleotide polymorphism (SNP) imputation, latent variables, and haplotype imputation. These methods are demonstrated in a simulation study and then applied to estimate the causal relation between C-reactive protein and each of fibrinogen and coronary heart disease, based on 3 SNPs in British Women’s Heart and Health Study participants assessed at baseline between May 1999 and June 2000. A complete-case ... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342331 Thu, 20 Oct 2011 04:00:00 +0100 5342331 http://www.medworm.com/index.php?rid=5342330&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2F1062%3Frss%3D1 Preterm delivery is a powerful predictor of newborn morbidity and mortality. Such problems are due to not only immaturity but also the pathologic factors (such as infection) that cause early delivery. The understanding of these underlying pathologic factors is incomplete at best. To the extent that unmeasured pathologies triggering preterm delivery also directly harm the fetus, they will confound the association of early delivery with neonatal outcomes. This, in turn, complicates studies of newborn outcomes more generally. When investigators analyze the association of risk factors with neonatal outcomes, adjustment for gestational age as a mediating variable will lead to bias. In the language of directed acyclic graphs, gestational age is a collider. The theoretical basis for colliders has... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342330 Thu, 20 Oct 2011 04:00:00 +0100 5342330 http://www.medworm.com/index.php?rid=5342329&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2F1054%3Frss%3D1 This study compares the results obtained from the most commonly used method to obtain herpes zoster data (rates obtained from administrative data) with results obtained when administrative data are supplemented by medical record review. Administrative billing code data identified 1,959 cases of herpes zoster in Olmsted County, Minnesota, adults between January 1, 1996, and December 31, 2001. Of those 1,959 cases, 1,669 (85.2%) could be confirmed by medical record review, a decrease in incidence rate of 14.8%, resulting in a decrease of 0.61/1,000 person-years when adjusted to the US adult population. Complication rates were also significantly different between the 2 methods. It is not clear if the 15% decrease in incidence rates would be seen in every administrative data set or if the lack... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342329 Thu, 20 Oct 2011 04:00:00 +0100 5342329 http://www.medworm.com/index.php?rid=5342328&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2F1044%3Frss%3D1 Prospective associations between quantity and frequency of alcohol consumption and cancer-specific mortality were studied using a nationally representative sample with pooled data from the 1988, 1990, 1991, and 1997–2004 administrations of the National Health Interview Survey (n = 323,354). By 2006, 8,362 participants had died of cancer. Cox proportional hazards regression was used to estimate relative risks. Among current alcohol drinkers, for all-site cancer mortality, higher-quantity drinking (≥3 drinks on drinking days vs. 1 drink on drinking days) was associated with increased risk among men (relative risk (RR) = 1.24, 95% confidence interval (CI): 1.09, 1.41; P for linear trend = 0.001); higher-frequency drinking (≥3 days/week vs. <1 day/week) was associated with incre... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342328 Thu, 20 Oct 2011 04:00:00 +0100 5342328 http://www.medworm.com/index.php?rid=5342327&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2F1036%3Frss%3D1 The authors hypothesized that the absence of cross-sectional associations of body mass index (BMI; weight (kg)/height (m)2) with peripheral arterial disease (PAD) in prior studies may reflect lower weight among persons who smoke or have poor health status. They conducted an observational study among 5,419 noninstitutionalized residents of 4 US communities aged ≥65 years at baseline (1989–1990 or 1992–1993). Ankle brachial index was measured, and participants reported their history of PAD procedures. Participants were followed longitudinally for adjudicated incident PAD events. At baseline, mean BMI was 26.6 (standard deviation, 4.6), and 776 participants (14%) had prevalent PAD. During 13.2 (median) years of follow-up through June 30, 2007, 276 incident PAD events occurred. ... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342327 Thu, 20 Oct 2011 04:00:00 +0100 5342327 http://www.medworm.com/index.php?rid=5342326&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2F1028%3Frss%3D1 Birth weight has been inversely associated with later blood pressure. Firstborns tend to have lower birth weight than their later-born peers, but the long-term consequences remain unclear. The study objective was to investigate differences between firstborn and later-born individuals in early growth patterns, body composition, and blood pressure in Brazilian adolescents. The authors studied 453 adolescents aged 13.3 years from the prospective 1993 Pelotas Birth Cohort. Anthropometry, blood pressure, physical activity by accelerometry, and body composition by deuterium were measured. Firstborns (n = 143) had significantly lower birth weight than later borns (n = 310). At 4 years, firstborns had significantly greater weight and height, indicating a substantial overshoot in catch-up growth. I... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342326 Thu, 20 Oct 2011 04:00:00 +0100 5342326 http://www.medworm.com/index.php?rid=5342325&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2F1017%3Frss%3D1 Although physical activity (PA) has been inversely associated with depressive symptoms, it is not clear whether regular PA and television watching are associated with clinical depression risk. The authors conducted a prospective analysis involving 49,821 US women from the Nurses’ Health Study who were free from depressive symptoms at baseline (1996). Information on PA was obtained from validated questionnaires completed in 1992, 1994, 1996, 1998, and 2000; analyses were conducted using the cumulative average of PA (minutes/day) with a 2-year latency period applied. Participants were asked about television-watching habits in 1992. Cox proportional hazards regression models adjusted for multiple risk factors were used to estimate relative risks of clinical depression (self-reported phy... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342325 Thu, 20 Oct 2011 04:00:00 +0100 5342325 http://www.medworm.com/index.php?rid=5342324&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2F1009%3Frss%3D1 Down syndrome birth is attributable to multiple maternal risk factors that include both genetic and environmental challenges, but there is limited understanding of the complicated interactions among these factors. In the present study, a case-control analysis of approximately 400 infants with or without suspected Down syndrome reported between 2003 and 2009 and their parents in and around Kolkata, India, was conducted. Maternal exposure to 2 environmental risk factors (smokeless chewing tobacco and oral contraceptive pills) was recorded, and families were genotyped with microsatellite markers to establish the origin of nondisjunction errors as well as recombination patterns of nondisjoined chromosome 21. With logistic regression models, the possible interactions among all of these risk fac... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342324 Thu, 20 Oct 2011 04:00:00 +0100 5342324 http://www.medworm.com/index.php?rid=5342323&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2F1002%3Frss%3D1 The relation between coffee intake and risk of amyotrophic lateral sclerosis (ALS) was investigated in 377 newly diagnosed ALS patients from 4 Italian population-based registries in the European ALS Consortium (EURALS Group) (2007–2010). For each patient, 2 age- and sex-matched hospital controls were selected, one from a neurology department and one from a nonneurologic department. Two additional healthy control groups were identified from local general practitioners’ (GPs’) lists (n = 99) and residents of the same area as a cancer cohort (n = 7,057). Coffee intake was defined in terms of status (ever consuming coffee daily for ≥6 months vs. never), duration, and history (never, former, or current). Ever coffee drinkers comprised 74.7% of ALS patients, 80.4% of neurolo... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342323 Thu, 20 Oct 2011 04:00:00 +0100 5342323 http://www.medworm.com/index.php?rid=5342322&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2F993%3Frss%3D1 Coffee consumption has been inconsistently associated with risk of stroke. The authors conducted a meta-analysis of prospective studies to quantitatively assess the association between coffee consumption and stroke risk. Pertinent studies were identified by searching PubMed and Embase from January 1966 through May 2011 and by reviewing the reference lists of retrieved articles. Prospective studies in which investigators reported relative risks of stroke for 3 or more categories of coffee consumption were eligible. Results from individual studies were pooled using a random-effects model. Eleven prospective studies, with 10,003 cases of stroke and 479,689 participants, met the inclusion criteria. There was some evidence of a nonlinear association between coffee consumption and risk of stroke... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342322 Thu, 20 Oct 2011 04:00:00 +0100 5342322 http://www.medworm.com/index.php?rid=5342321&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2FNP-c%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342321 Thu, 20 Oct 2011 04:00:00 +0100 5342321 http://www.medworm.com/index.php?rid=5342320&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2FNP-b%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342320 Thu, 20 Oct 2011 04:00:00 +0100 5342320 http://www.medworm.com/index.php?rid=5342319&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2FNP-a%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342319 Thu, 20 Oct 2011 04:00:00 +0100 5342319 http://www.medworm.com/index.php?rid=5342318&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F9%2FNP%3Frss%3D1 (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5342318 Thu, 20 Oct 2011 04:00:00 +0100 5342318 http://www.medworm.com/index.php?rid=5301049&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F8%2F984%3Frss%3D1 Modified Poisson regression, which combines a log Poisson regression model with robust variance estimation, is a useful alternative to log binomial regression for estimating relative risks. Previous studies have shown both analytically and by simulation that modified Poisson regression is appropriate for independent prospective data. This method is often applied to clustered prospective data, despite a lack of evidence to support its use in this setting. The purpose of this article is to evaluate the performance of the modified Poisson regression approach for estimating relative risks from clustered prospective data, by using generalized estimating equations to account for clustering. A simulation study is conducted to compare log binomial regression and modified Poisson regression for ana... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5301049 Thu, 06 Oct 2011 04:00:00 +0100 5301049 http://www.medworm.com/index.php?rid=5301048&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F8%2F977%3Frss%3D1 This study evaluated for the first time the test-retest reliability of SRH among US adults. Analyses were based on a nationally representative sample of 9,235 adults interviewed in the 2005–2008 National Health and Nutrition Examination Survey (NHANES). Respondents reported SRH on 2 occasions (about 1 month apart). Kappa statistics, polyserial correlations, and agreement tabulations were used to assess reliability across population subgroups; regression models tested the association of sociodemographic factors and the stability of the rating. Nearly 40% of respondents changed their health rating between interviews, indicating moderate test-retest reliability of SRH. Reliability differed significantly by sociodemographic characteristics: Racial/ethnic minorities and adults with less e... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5301048 Thu, 06 Oct 2011 04:00:00 +0100 5301048 http://www.medworm.com/index.php?rid=5301047&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F8%2F969%3Frss%3D1 Selection bias and confounding are concerns in cohort studies where the reason for inclusion of subjects in the cohort may be related to the outcome of interest. Selection bias in prevalent cohorts is often corrected by excluding observation time and events during the first time period after inclusion in the cohort. This time period must be chosen carefully—long enough to minimize selection bias but not too long so as to unnecessarily discard observation time and events. A novel method visualizing and estimating selection bias is described and exemplified by using 2 real cohort study examples: a study of hepatitis C virus infection and a study of monoclonal gammopathy of undetermined significance. The method is based on modeling the hazard for the outcome of interest as a function of... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5301047 Thu, 06 Oct 2011 04:00:00 +0100 5301047 http://www.medworm.com/index.php?rid=5301046&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F8%2F958%3Frss%3D1 This study confirms the independent association of elevated free PS levels with future risk of CHD, although elevated PS levels added only modestly to prediction metrics. The novel finding of increased CHD risk, particularly when CRP and PS levels are high, requires further study. (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5301046 Thu, 06 Oct 2011 04:00:00 +0100 5301046 http://www.medworm.com/index.php?rid=5301045&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F8%2F949%3Frss%3D1 In conclusion, the addition of cystatin C or serum creatinine to FRSVs does not improve CVD risk prediction among adults without clinical CVD. (Source: American Journal of Epidemiology) American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5301045 Thu, 06 Oct 2011 04:00:00 +0100 5301045 http://www.medworm.com/index.php?rid=5301044&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F8%2F945%3Frss%3D1 A 2006 study from the United Kingdom found that penicillin use may decrease the risk of multiple sclerosis (MS). To confirm this finding, the authors conducted a nationwide case-control study in Denmark, using the Danish Multiple Sclerosis Registry to identify 3,259 patients with MS onset from 1996 to 2008, and selected 10 population controls per case (n = 32,590), matched on sex and age. Through the National Prescription Database, prescriptions for antibiotics redeemed from 1995 to 2008 and before the date of first MS symptom/index date were identified. Conditional logistic regression analysis was used to compute odds ratios associating antibiotic use with MS occurrence. In total, 1,922 patients (59%) redeemed penicillin prescriptions before the index date and 2,292 (70%) redeemed any typ... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5301044 Thu, 06 Oct 2011 04:00:00 +0100 5301044 http://www.medworm.com/index.php?rid=5301043&cid=s_28380_54_f&fid=28380&url=http%3A%2F%2Faje.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F174%2F8%2F934%3Frss%3D1 Knowledge of the association between body mass index (weight (kg)/height (m)2) and premature death in young adulthood is very limited, especially for specific causes of death. Using the US National Health Interview Survey linked mortality files, the authors examined the relation between body mass index and premature death from all causes, cardiovascular disease (CVD), and cancer among 112,328 persons aged 18–39 years who participated in the National Health Interview Survey in the years 1987, 1988, and 1990–1995. During an average of 16 years of follow-up (ending on December 31, 2006), there were 3,178 deaths: 573 from CVD and 733 from cancer. Hazard ratios and 95% confidence intervals were estimated using multivariate proportional hazards models adjusting for age, gender, race/... American Journal of Epidemiology journals http://www.medworm.com/rss/comments.php?id=5301043 Thu, 06 Oct 2011 04:00:00 +0100 5301043