Workers' smoking histories are not measured in many occupational cohort studies. Here we discuss the use of negative control outcomes to detect and adjust for confounding in analyses that lack information on smoking. We clarify the assumptions necessary to detect confounding by smoking and the additional assumptions necessary to indirectly adjust for such bias. We illustrate these methods using...

The aim of this study was to evaluate whether the completeness of case ascertainment during the follow-up of a cohort differed between the exposed and the nonexposed groups in Korea Radiation Effect and Epidemiology Cohort (KREEC). The completeness was defined as the proportion of the number of detected cases to the number of estimated cases, in which the estimation was performed by capture-rec...

BACKGROUND Chinese women's reproductive patterns have changed significantly over the past several decades. However, relatively little is known about the pace and characteristics of these changes either overall or by region and socioeconomic status. METHODS We examined the cross-sectional data from the China Kadoorie Biobank cohort study that recruited 300 000 women born between 1930 and 1974 ...

OBJECTIVE The main objective of this study is to evaluate the effect of heavy drinking on alcohol-related injuries. MATERIAL AND METHODS We carried out an open cohort study among university students in Spain (n=1,382). Heavy drinking and alcohol-related injuries were measured by administrating AUDIT questionnaires to every participant at the ages of 18, 20, 22 and 24. For data analysis we use...

In occupational epidemiology, exposure-response analyses play an important role in the evaluation of the etiologic relevance of chemical and physical exposures. The standardized mortality or morbidity ratio (SMR) has been commonly used in occupational cohort studies. Statistical approaches to evaluate exposure-response patterns using SMRs have mostly been limited to analyses in which the exposu...

BACKGROUND Previous research has documented that exposure to parental separation/divorce during childhood can be associated with long-term consequences into adulthood. This study sought to extend this literature by examining associations between childhood exposure to parental separation/divorce and later parenting behavior as an adult in a New Zealand birth cohort. METHODS Data were drawn fro...

OBJECTIVES To investigate how results of the association between education and weight change vary when weight change is defined and modelled in different ways. DESIGN Longitudinal cohort study. PARTICIPANTS 60 404 men and women participating in the Social, Environmental and Economic Factors (SEEF) subcomponent of the 45 and Up Study-a population-based cohort study of people aged 45 years or...

Large numbers of randomised controlled trials (RCT) have been carried out in order to investigate diet-disease relationships. This article examines eight sets of studies and compares the findings with those from epidemiological studies (cohort studies in seven of the cases). The studies cover the role of dietary factors in blood pressure, body weight, cancer and heart disease. In some cases, th...

Background. Attrition is a major cause of potential bias in longitudinal studies and clinical trials. Attrition rate above 20% raises concern of the reliability of the results. Few studies have looked at the factors behind attrition in follow-ups spanning decades. Methods. We analyzed attrition and associated factors of a 30-year follow-up cohort of subjects who were born with perinatal risks f...

Progress has recently been made in understanding the genetic basis of schizophrenia and other psychiatric disorders. Longitudinal studies are complicated by participant dropout, which could be related to the presence of psychiatric problems and associated genetic risk. We tested whether common genetic variants implicated in schizophrenia were associated with study nonparticipation among 7,867 c...