The investigation of the relationship between the effects of the exposure to noise on hearing and cigarette smoking as well as cotinine

The investigation of the relationship between the effects of the exposure to noise on hearing and cigarette smoking as well as cotinine. Abant Izzet Baysal University School of Medicine, Otorhinolaryngology Thesis, Bolu, 2012. In all industrialized countries, noise has become a significant factor causing health problems that influence hearing. In recent years, it has been argued that in addition to many other factors, cigarette smoking leads to the vulnerability to noise-induced hearing loss (NIHL). This study aimed to evaluate and compare noise-induced hearing loss cases through audiometry and distortion product otoacoustic emission (DPOAE) as well as to investigate the effects of dose-dependent cigarette smoking on NIHL through audiometry and otoacoustic emission by assessing the levels of serum cotinine. This study was designed as a prospective longitudinal clinical study. The data were collected in 2009 and 2011 in two years interval. Before the research, workers were given demographic inventories and questionnaires that reveal information related to their age, working hours, cigarette smoking status, the amount and the duration of cigarette smoking, systemic diseases, whether they have otological diseases and their medicine history. The levels of serum cotinine in the peripheral venous blood samples that were taken from the cigarette-smoking subjects were examined in two years interval and all participants were given audiometry (500, 1000, 1500, 2000, 3000, 4000, 6000, 8000 Hz and PTA) and DPOAE (1000, 1400, 2000, 2800, 4000 Hz) tests at the beginning and at the end of the study. In statistical analyses, PASW (ver.18) program was utilized. The level of significance was considered as ?=0,05. 170 male workers participated in this study. There were 82 workers in the cigarette-smoking group and 88 workers in the non-smoker group. In the second cotinine levels and the second audiometric measurements, it was found out that there was a significant relationship among 1500 Hz, 2000 Hz, 3000 Hz and PTA (p<0,05). It was also discovered that there was a significant relationship between the the second cotinine levels and the second DPOAE values that are 2nd DP1400 Hz,2800 Hz, 4000 Hz, 2nd SNR 2800Hz, 4000 Hz values (p<0,05). A strong correlation was found between two of these values, DP 4000Hz and SNR 4000Hz, and the second kotinin value (respectively r=-0,610; -0,601). These findings are of great importance in that they reveal that as hearing loss increases, cigarette smoking could influence hearing. When the interaction between the results of the tests given to the cigarette-smoking group and the non-smoking group at the beginning and at the end of the second year of the research and the groups was explored, it was discovered that there was not significant relationships in the measurements in all frequencies (p>0,05). This study is the first one to investigate the relationship between cotinine and smoking habits as well as exposure to noise. It could be indirectly concluded that cigarette smoking status does not have an effect on the development of NIHL, but the levels of serum cotinine gains significance in individuals relatively suffering from hearing loss and cotinine could be influencial in the development of this hearing loss. Further studies need to be carried out for more stronger interpretations related to the subject.