Is there a relevant effect of noise and smoking on hearing? A population-based aging study.

The objectives of the present study were to evaluate both the respective and combined effects of occupational noise exposure and smoking on hearing, taking age into consideration. The evaluation was conducted using 1478 subjects without a history of ear disease out of a population-based sample of 2267 adults, aged 40 79 years. Pure-tone audiometry and a questionnaire were administered. A deleterious effect of noise exposure on hearing was significantly observed in both genders at many frequencies after adjustment for age, income, and education. The smoking habit alone significantly affected hearing deterioration at 4000 Hz in noise-unexposed males. The combined effect of noise and smoking was not interactive but additive. A dose-response effect of smoking on hearing loss was observed in middle-aged males without noise exposure. Smoking and noise exposure were associated with hearing loss respectively.. This result is noteworthy for the preservation of good hearing especially at the beginning of aging.