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