Biostatistics & Research · single question
A group of smokers is followed for 8 years to monitor incidence of oral cancer. Which study type is this?
Show answer and explanation
Correct answer: C. Cohort study
- A. An RCT would randomly ASSIGN people to smoke or not smoke — clearly unethical and impossible; this observational study is a cohort design.
- B. Case-control studies start with disease status (cases with cancer vs. controls without) and look backward — they do not start with exposure and follow forward.
- C. Correct. Following a defined group (smokers) forward in TIME to observe who develops a disease (oral cancer) is the definition of a PROSPECTIVE COHORT study. The cohort is classified by exposure (smoking) at the start and followed to measure incidence.
- D. Cross-sectional studies take a single snapshot in time — they do not follow people over 8 years.
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