A researcher studies a group of 500 textile workers exposed to cotton dust and 500 unexposed workers over 10 years to determine incidence of byssinosis. The relative risk for developing byssinosis in exposed workers is 6.0. Which type of study design is this?
- A Prospective cohort study ✓
- B Case-control study
- C Cross-sectional study
- D Ecological study
Correct answer: A. Prospective cohort study
Explanation
A prospective cohort study follows defined groups (exposed and unexposed) forward in time to measure incidence of disease, allowing direct calculation of relative risk. The temporal sequence here — exposure identified first, then disease incidence measured — and the presence of a true incidence rate confirm cohort design. Case-control studies start from disease outcome and calculate odds ratio, not relative risk directly.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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