Researchers studying triggers of acute myocardial infarction interview patients within hours of the event about heavy physical exertion in the preceding hour and in an identical one-hour period the previous day. Each patient thus serves as his own control. Which study design is this?
- A Nested case-control study
- B Retrospective cohort study
- C Case-crossover study ✓
- D Cross-over randomized trial
Correct answer: C. Case-crossover study
Explanation
The case-crossover design examines transient exposures immediately before an acute event, comparing exposure frequency in a hazard period with a defined control period within the same individual. Self-matching eliminates fixed confounders such as age and chronic habits. A cross-over randomized trial involves planned intervention sequences, and a retrospective cohort follows groups forward from past exposure records.
Reference: Gordis Epidemiology, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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