In a cross-sectional study on hypertension prevalence, the Mantel-Haenszel method is used to control for age confounding. The Mantel-Haenszel odds ratio is 2.1. The crude odds ratio was 3.8. This finding suggests that age was acting as a:
- A Effect modifier
- B Mediator on the causal pathway
- C Confounder positively associated with both exposure and disease ✓
- D Precision variable only
Correct answer: C. Confounder positively associated with both exposure and disease
Explanation
When stratification or adjustment reduces the crude measure of association toward the null, the variable being controlled (age here) was a positive confounder — associated with both the exposure and outcome and distorting the estimate upward. Effect modification produces heterogeneous stratum-specific estimates; a mediator lies on the causal pathway and should not be adjusted for.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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