Consider each of the following scenarios and explain whether the variable in question is a confounder:
1. 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.
2. 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.
3. Explain whether smoking is a confounder.
Gender is a confounder in this study
Gender is not a confounder since they are not studying about gender but about men in general
1. In the first scenario, the variable in question is gender, and it is not a confounder. The reason is that the study is specifically conducted among women who do not smoke. By restricting the study to women who do not smoke, any potential confounding effects of gender will be minimized or eliminated since the study population is homogeneous in terms of gender.
2. In the second scenario, the variable in question is smoking. Here, smoking could be considered a confounder. The study aims to investigate the relationship between liver cirrhosis and alcohol use, but smoking is associated with both drinking alcohol and being a risk factor for liver cirrhosis. Since smoking is associated with both the exposure (alcohol use) and the outcome (liver cirrhosis), it acts as a confounder because it can distort the relationship between alcohol use and liver cirrhosis.
3. In the third scenario, the variable in question is smoking. To determine whether smoking is a confounder, we need more information about the specific study being conducted. Since this information is not provided, we cannot definitively state whether smoking is a confounder. However, if smoking is associated with both the exposure and the outcome of interest, it is likely to be a confounder.