Introduction: The biological processes involved in noise-induced hearing loss (NIHL) are still
unclear. The involvement of inflammation in this condition has been suggested.
Objective: To investigate the association between interleukin --- 6 (IL-6) polymorphism and
susceptibility to NIHL.
Methods: This was a cross-sectional study with a sample of 191 independent elderly individuals
aged >60 years of age. Information on exposure to occupational noise was obtained by
interviews. Audiological evaluation was performed using pure tone audiometry and genotyped
through PCR by restriction fragment length polymorphism --- PCR-RFLP. Data were analyzed using
the chi-square test and the odds ratio (OR), with the significance level set at 5%.
Results: Among elderly with hearing loss (78.0%), 18.8% had a history of exposure to occupational
noise. There was a statistically significant association between the genotype frequencies
of the IL-6
−174 and NIHL. The elderly with the CC genotype were less likely to have hearing
loss due to occupational noise exposure when compared to those carrying the GG genotype
(OR = 0.0124; 95% CI 0.0023---0.0671; p < 0.001).
Conclusion: This study suggests there is an association of polymorphisms in the IL-6 gene at
position --- G174C with susceptibility to noise-induced hearing loss.