The case–control association study is a powerful method for identifying genetic variants that influence disease risk. In a typical study, a researcher genotypes a set of individuals who have a disease ...

An approach where the dependent variables are measured before and after an intervention has been delivered. The intervention can either be delivered by the investigator or by others (observational ...

In a nationally representative sample of 1.1 million homes, we compared the prevalence of smoking among 33,000 deceased women and 41,000 deceased men (case subjects) with the prevalence of smoking ...