American Board of Internal Medicine (ABIM) Certification Practice Exam

What type of studies investigate the outcomes of similar patients with different exposures?

1. Case-control studies

2. Cohort studies

3. Cross-sectional studies

4. Experimental studies

The correct answer is: Cohort studies

Cohort studies are designed to observe the outcomes in groups of patients who share common characteristics but have different exposures to a particular risk factor or treatment. In a cohort study, participants are recruited based on their exposure status and are followed over time to assess the incidence of outcomes such as diseases or health events. This design allows researchers to establish a temporal relationship between exposures and outcomes, providing insights into how various exposures (e.g., lifestyle choices or medications) impact health over time. This method is particularly useful because it can help identify associations between exposures and outcomes, making it easier to understand the causal relationships involved. By comparing the health outcomes of different cohorts—those exposed to a certain risk factor versus those not exposed—researchers gain valuable information about the effects of these exposures on health. In contrast, case-control studies typically start with patients who have a particular outcome and look backward to identify previous exposures, making them less suited for observing the impact of current exposure on future outcomes. Cross-sectional studies assess exposure and outcome simultaneously but do not provide insight into the temporal relationship, while experimental studies involve random assignment to treatment groups to determine causality, which is different from comparing outcomes across different exposures.