a. A study of the relationship between exercise and heart attacks that is conducted among women who do not smoke. Explain whether gender is a confounder.

Question

b. A case-control study of the relationship between liver cirrhosis and alcohol use. In this study, smoking is associated with drinking alcohol and is a risk factor for liver cirrhosis among both non-alcoholics and alcoholics. Explain whether smoking is a confounder.

Answer 1

a. How can gender be a confounder, if only one gender is used?

b. Would the cirrhosis found be caused by drinking, smoking or an interaction of the two? (An ANOVA could separate out the effects of these factors.)

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