Association of the C47T polymorphism in superoxide dismutase gene 2 with noise-induced hearing loss: a meta-analysis.

INTRODUCTION Currently, there is limited information about the relationship between manganese superoxide dismutase (sod2) c47t polymorphism and susceptibility to noise-induced hearing loss (NIHL). OBJECTIVE The aim of this meta-analysis was to clarify the association between SOD2 C47T polymorphism and NIHL. METHODS A search in PubMed and Web of Science was performed to collect data. All full-text, English-written studies containing sufficient and complete case-and-control data about the relationship between SOD2 C47T polymorphism and NIHL were included. Three eligible studies, comprising 1094 subjects, were identified. pooled odds ratios (ORs) and 95% confidence intervals (CI) were calculated to evaluate the strength of the association between SOD2 C47T polymorphism and NIHL. RESULTS No significant association between C47T polymorphism and risk of NIHL was found with the following combinations: T vs. C (OR=0.83; 95% CI=0.63-1.09); TT vs. CC (OR=0.49; 95% CI=0.22-1.09); CT vs. CC (OR=0.54; 95% CI=0.25-1.17); TT vs. CC+CT (OR=0.82; 95% CI=0.50-1.32); CC vs. TT+TC (OR=0.49; 95% CI=0.23-1.04). However, in subgroup analysis, a significant association was found for TT vs. CC+CT (OR=0.77; 95% CI=0.42-1.41) in the Chinese population. CONCLUSION The present meta-analysis suggests that SOD2 C47T polymorphism is significantly associated with increased risk of NIHL in the Chinese population. Further large and well-designed studies are needed to confirm this association.