Among 5,000 workers exposed to a chemical, 60 deaths from bladder cancer occurred during follow-up. Applying national age-specific mortality rates to the cohort yields 40 expected deaths. The standardized mortality ratio is:
- A 66
- B 120
- C 150 ✓
- D 240
Correct answer: C. 150
Explanation
SMR equals observed deaths divided by expected deaths multiplied by 100: 60 divided by 40 gives 1.5, so SMR = 150, meaning 50% excess mortality relative to the standard population. Option A inverts the ratio, option B corresponds to 48 expected deaths, and option D doubles rather than adds the excess. SMR is the standard indirect standardization measure used in occupational cohort studies where direct age-specific rates are unavailable.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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