Among 5,000 coal miners, 60 deaths occurred during the study period, whereas 40 deaths would have been expected had national age-specific mortality rates applied to this cohort. The standardized mortality ratio (SMR) and its correct interpretation are:
- A 150%, indicating a 50% excess of deaths compared with the general population ✓
- B 67%, indicating mortality 33% lower than the general population
- C 150%, indicating 150 additional deaths above expectation
- D 66%, indicating the cohort contributes two-thirds of expected deaths
Correct answer: A. 150%, indicating a 50% excess of deaths compared with the general population
Explanation
SMR equals observed deaths divided by expected deaths, multiplied by 100: 60 divided by 40 times 100 gives 150. An SMR of 150 means the cohort experienced 50% more deaths than expected under national age-specific rates. Option C misreads the ratio as a count difference, since the excess is 20 deaths, not 150. Indirect standardization, as used here, is the standard method for comparing an occupational cohort with general population rates.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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