Question

An epidemiologists conducted cohort study of the relationship between alcohol consumption and depression. She stratified her analysis by history of domestic violence. She found that the relative risk among women who experience domestic violence was 0.9. The relative risk among men who did not experience domestic violence was 2.0. Is history of domestic violence a CONFOUNDER for the relationship between alcohol and depression? Why or why not

Answer 1

Yes ..

According to the given data domestic violence is a cofounder in relationship of alcohal consumption and depression in this cohort study. Cofounders are the factors that is attached both with exposure and outcome . Here it is seen that in female facing domestic violence have a a protective effect of alcohol and depression, with relative risk less than 1 but in other case women having alcohol have greater chances to get depression with a relative risk of 2. So in absence of stratification it would have changed the final result drastically.

This is the reason is why domestic violence is a confounder, and here confounding factor is removed by stratification.