In population-based cohort studies, a sample, or even the entirety, of a defined population is
selected for longitudinal assessment of exposure-outcome relations. Because of their …

Collection of accurate exposure information on study participants is a major objective of all
epidemiologic studies. The term exposure is used here to include not only exposures to …

The occurrence of events over time unifies epidemiologic research. Regardless of the study
hypothesis and design, the disease-causing actions of exposures and modifying factors are …

Epidemiologists frequently study the experience of a population over time to estimate the
association between exposure and outcome. These studies generally use case–control …

Background Participants in cohort studies are frequently selected from restricted source
populations. It has been recognised that such restriction may affect the study validity …

It is known that unbiased estimates of the relative risk in a cohort study may be obtained by a
matched case-control analysis that compares each case with a random sample of controls …

Measurement error in explanatory variables and unmeasured confounders can cause
considerable problems in epidemiologic studies. It is well recognized that under certain …

It has been widelyaccepted that one reason for inconsistent or contradictory results of
epidemiologic studies is bias. Therefore, an appreciation of potential sources of bias has …

As empirical evidence in support of a multifactor etiology has accumulated in various areas
of chronic disease research, epidemiologists have become increasingly interested in the …

The author proposes that epidemiologic studies should more often assess the associations
of a single exposure with multiple outcomes simultaneously. Such “outcome-wide …