A researcher studying the relationship between dietary fat intake (exposure) and breast cancer (outcome) uses a cross-sectional design. The major limitation of this study design in establishing causality is:
- A It cannot calculate prevalence
- B It cannot determine temporal relationship between exposure and outcome ✓
- C It requires a very large sample size
- D It is prone to Neyman bias only
Correct answer: B. It cannot determine temporal relationship between exposure and outcome
Explanation
Cross-sectional studies measure exposure and outcome simultaneously, making it impossible to establish which came first (temporality), one of Bradford Hill's criteria for causation. They are excellent for estimating prevalence and generating hypotheses but cannot distinguish whether the exposure preceded the disease. Both cohort and experimental designs allow temporal relationship assessment.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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