Prevalence rate ratio of hearing loss for the combinations of occupational exposure to noise and smoking among 4624 male workers in a steel factory in Japan, 1999
| Non-smoker | Smoker | |||
|---|---|---|---|---|
| Occupational noise exposure | PRR* | 95% CI | PRR | 95% CI |
| PRR, prevalence rate ratio; CI, confidence interval. | ||||
| *Calculated by the Cochran-Mantel-Haenszel method, stratified by age group. | ||||
| 1000 Hz | ||||
| No | 1 | Reference | 1.14 | 0.82 to 1.58 |
| Yes | 1.55 | 0.98 to 2.45 | 1.50 | 1.05 to 2.15 |
| 4000 Hz | ||||
| No | 1 | Reference | 1.57 | 1.31 to 1.89 |
| Yes | 1.77 | 1.36 to 2.30 | 2.56 | 2.12 to 3.07 |