OBJECTIVETo investigate the association between the single nucleotide polymorphisms (SNPs) of paraoxonase-2 (PON2) gene and the susceptibility to occupational noise-induced deafness among Chinese Han population exposed to high noise levels [>85 dB (A)].

METHODSA case-control study was conducted in Chinese Han population exposed to high noise levels. The subjects were divided into case group (n = 127) and control group (n = 136) according to the Diagnostic criteria of occupational noise-induced deafness (GBZ 49-2007). The case group was composed of 127 workers with a mean binaural high-frequency hearing threshold not less than 40 dB, as measured using an electro-audiometer, while the control group was composed of 136 workers with a mean binaural high-frequency hearing threshold less than 40 dB, as measured using the electro-audiometer, who were on shift in the same position as the cases and matched with them for age, sex, and years of noise exposure. Peripheral venous blood (2 ml) was collected from each subject during physical examination to extract genomic DNA, and genotypes were identified using a TaqMan probe.

RESULTSPON2 genotypes rs7493 CG+GG, rs7785846 CT+TT, rs12026 CG+GG, and rs7786401 GT+TT were the risk factors for occupational noise-induced deafness, and the adjusted odds ratios (95%confidence intervals) were 5.87 (3.11∼11.07), 5.92 (3.10∼11.32), 5.53 (2.93∼10.45), and 5.93 (3.10∼11.34), respectively. In addition, the higher the noise exposure levels, the higher the risk of developing occupational noise-induced deafness among the individuals carrying mutant genotypes.

CONCLUSIONPON2 genotypes rs7493 CG+GG, rs7785846 CT+TT, rs12026 CG+GG, and rs7786401 GT +TT may be associated with the susceptibility to occupational noise-induced deafness among Chinese Han population exposed to high noise levels, and the effects of mutant genotypes and noise exposure levels may be mutually enhanced.