Hearing impairment due to cigarette smoking and simultaneous exposure to occupational noise

  Abstract   Background : Noise is the most common hazard in the workplace and noise induced   hearing loss considered to be the most common occupational disease as well.   Cigarette smoking, in some studies, has been known to induce hearing loss. The purpose   of this study was to evaluate the effect of contemporary exposure to occupational   noise and cigarette smoking on hearing.   Methods : 478 assembly workers of an automobile plant which were exposed to   the noise more than TLV (threshold limit value) level included in this study. After   considering the exclusion criteria, all participants according to the smoking status   were divided in smoker and nonsmoker groups and compared for hearing impairment.   Hearing impairment in this study was assessed with the offered method of   American Academy of Otolaryngology (AAO).   Results : Of 478 assembly workers, 225 persons were smokers and others non   smokers. Prevalence of hearing impairment in smokers was significantly higher   (p<0.001). Hearing impairment had a significant relation with smoking status even   after adjusting for cofounders like age and duration of work (OR=8.23, 95%   CI=3.63-18.66).   Conclusion : The results of this study suggested that cigarette smokers had more   hearing impairment than non smokers. According to these results we concluded that   in working environments, especially in noisy ones, workers must be encouraged to   quit smoking and regular audiometric tests, especially for smokers, must be applied.   We must consider not only the noise, but indeed all effective elements of hearing impairment   in working environment that could compromise the hearing.