Disadvantage of case control study when compared to cohort study:
**Core Concept**
Case-control studies are a type of observational study design used to investigate the association between a particular exposure and a specific outcome. They are particularly useful for studying rare diseases or outcomes. However, they have inherent limitations compared to cohort studies.
**Why the Correct Answer is Right**
Case-control studies are prone to recall bias, as participants are selected based on the presence or absence of the outcome, and exposure information is often obtained retrospectively. This can lead to biased estimates of the association between the exposure and outcome. Additionally, case-control studies are often subject to selection bias, as participants may not be representative of the broader population. Furthermore, case-control studies cannot establish temporality, which is a critical aspect of causality.
**Why Each Wrong Option is Incorrect**
**Option A:** Temporal relationship cannot be established in cohort studies either. This is incorrect because while cohort studies can establish temporality, they are still susceptible to other biases and confounding variables.
**Option B:** Bias in case-control studies is due to the study design, not the type of disease. This is incorrect because the type of disease being studied does not inherently cause bias in case-control studies.
**Option C:** Confounding variables can affect both case-control and cohort studies. This is incorrect because while confounding variables are a concern in both study designs, they do not specifically disadvantage case-control studies.
**Clinical Pearl / High-Yield Fact**
When interpreting observational studies, it's essential to consider the study design and potential biases, as they can significantly impact the results and conclusions drawn.
**Correct Answer: C. Confounding variables can affect both case-control and cohort studies.**