The effects of dyslipidemia on noise-induced hearing loss in petrochemical workers in the Southwest of Iran

BACKGROUND: Research has shown that the decrease in the inner diameter of vessels caused by hyperlipidemia lowers the capacity for blood oxygen delivery to the cochlea. This leads to impaired cochlear metabolism and causes hearing problems. OBJECTIVE: The effects of dyslipidemia on noise-induced hearing loss in workers were examined. METHODS: This descriptive cross-sectional study was performed on 692 male employees in a petrochemical industry in the southwest of Iran exposed to 85 dB noise. Clinical audiometry and blood sample tests were used to evaluate the hearing and prevalence indices of dyslipidemia (cholesterol, triglyceride, HDL and LDL). The data were analyzed using SPSS software version 25 (p = 0.05). RESULTS: The results showed that the prevalence of dyslipidemia was 24.5% with abnormal relative triglyceride frequency of 49.5%, HDL of 28%, LDL of 33%, and total blood cholesterol level of 37.8%. There was no significant relationship between NIHL and dyslipidemia (p > 0.09). However, the major NIHL drops at different frequencies were in the individuals with dyslipidemia. The parameters age and dyslipidemia increased NIHL odds ratio (95% C.I.) by 1.130 (1.160-1.100) and 1.618 (2.418-1.082) respectively. CONCLUSION: The rate of hearing loss in individuals with dyslipidemia increases at different frequencies and it leads to an increase of the OR of NIHL in individuals with dyslipidemia. We can control dyslipidemia and its effective factors. The NIHL is more common in people exposed to noise.