Environmental noise in Beirut, smoking and age are combined risk factors for hearing impairment.

Effect of smoking and environmental noise on hearing impairment was investigated in 440 people aged 21-50 years living in Beirut. Participants were divided into 4 groups: nonsmokers and smokers living in noisy areas (70-90 dBA) and non-smokers and smokers living in quiet areas (45-55 dBA). Smoking was associated with hearing loss at 8000 Hz, in both bivariate and multivariate analysis. An additive interaction at high frequencies (mostly at 8000 Hz) between smoking and noise appeared after age 40 years. At age 21-39 years, neither smoking nor environmental noise had a significant adverse effect on hearing capacity at low frequencies.