A study of 10,000 persons finds that the standardized mortality ratio (SMR) for a certain industry is 1.5 (95% CI: 1.2–1.9). The most appropriate interpretation is:
- A The exposed group has 1.5 times the absolute risk of death compared to the general population
- B The observed deaths are 50% more than expected, and this is statistically significant ✓
- C The 95% CI indicates the result is not statistically significant as it includes 1
- D SMR of 1.5 means 50% fewer deaths occurred than expected
Correct answer: B. The observed deaths are 50% more than expected, and this is statistically significant
Explanation
SMR = (Observed deaths / Expected deaths) × 100, or expressed as a ratio = Observed/Expected. An SMR of 1.5 with 95% CI not including 1.0 (range 1.2–1.9) indicates statistically significant excess mortality: the observed deaths are 50% more than expected based on general population rates. Since the CI excludes 1.0, the result is statistically significant. An SMR <1 would indicate fewer deaths than expected.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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