Abstract
Objective: Both genetic and environmental factors contribute to noise-induced hearing loss (NIHL). The objective of this study is to investigate the hypothesis that Glutathione S-transferase (GST) genetic polymorphisms is related to susceptibility to developing NIHL caused by music exposure.
Method: This cross-sectional study recruited high school students who habitually listen to music with portable players. PTA, distortion product otoacoustic emission (DPOAE), and questionnaire were obtained. Cumulative noise exposure (CNE) was calculated by listening time and volume of using portable players. Effects of GST1, GSTM1, and GSTP1-105 on NIHL were analyzed.
Results: A total of 312 subjects were analyzed. Mean of PTA at high frequency (average of 3000, 4000, and 6000 Hz) was 8.07 dB HL (SD = 5.98). DPOAE amplitude level at high frequency was 20.28 dB SPL (SD = 5.10). Mean of CNE was 84.57 dB-year (SD = 11.42). With the regression analysis model, there was a good dose-response relationship between CNE and DPOAE amplitude levels at high frequency (P < .05). Furthermore, those subjects, with GSTT1-null, GSTM1-null, and GSTP1-105 Ile/Ile genotypes, had higher susceptibility for developing hearing threshold elevation at high frequency (P < .05).
Conclusion: This study identified that GST genetic polymorphisms might modify the susceptibility of hearing threshold elevation at high frequency caused by music exposure. Moreover, investigations of other genotypic variants involved in oxidative stress response for elucidating the gene-environment interaction for NIHL are warranted.
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