The Association Of Apoptosis-related Gene Polymorphism And Behavioral Factors With Noise-induced Hearing Loss In Chinese Han Population

Objective: To explore the relationship of apoptosis-related gene polymorphism,environmental factors and noise-induced hearing loss(NIHL), and gene-environment interaction on NIHL in Chinese Han population.Methods: A 1:1 matched case-control study was conducted on a total of 544 samples selected from a population of 1549 noise-exposed workers in Hangzhou.workers With the hearing threshold at high frequency﹥25d B of hearing level(HL) were selected as observing cases,while those who worked in same workshop with the observing cases,had matched age,gender,years of noise exposure and hearing thresholds≦25d B(HL) at each frequency were selected as controls.Genotypes were measured by PCR-LDR.SPSS version 20.0 Statistical analysis adopt t test,Chi-square test and multiple factors logistic regression.Linkage disequilibrium and haplotype was analysed by SHEsis software. dichotomy analysis was used in the analyze of interaction between environmental risk factors and gene polymorphism.Results:1. Educational level and sleep duration show protective effect for NIHL,higher educational level NIHL risk was 0.382 times than the lower(P = 0.025); Sleep time in 22:00- 23:00 and < 22:00 risk were 0.477 times and 0.182 times than the >23:00(P﹤0.001). Using headphones and make phone call are risk factors for NIHL,wear headphones 0-2h every day is 2.033 times(P = 0.002) comparing with those no using; calls≧16min a day is 2.477 times than those no calls(P = 0.012).2.Frequencies of each genotype did not indicate deviations form Hardy-Weinberg equilibrium(P >0.05)except the sample rs3769823 and rs7921977.3. Analysis showed that CASP3 gene rs1049216 and rs6948 polymorphism reduce the risk of NIHL(ORCT+TT vs CC= 0.645, 95%CI=0.428~0.973; ORAC+CC vs AA= 0.655, 95%CI=0.431~0.995); Individuals with haplotype CT showed a significantly association with NIHL(OR=0.691,95%CI=0.501~0.954).4.CASP7 gene rs2227310、rs12415607 polymorphism reduce the risk of NIHL(S14:rs2227310:ORGG vs CC=0.372,95%CI=0.200~0.693;ORGG vs CC+CG=0.397,95%CI=0.224~0.704;rs12415607:ORAA vs CC=0.36,95%CI=0.189~0.687;ORAA vs CC+AC=0.413,95%CI=0.231~0.739),while rs1127687 polymorphisms increase the risk of NIHL(ORAG vs GG=1.605,95%CI=1.061~2.426;ORAG+AA vs GG=1.6,95%CI=1.079~2.374;ORGG+AA vs AG=0.638,95%CI=0.423~0.961).Individuals with haplotype AGG showed a significantly association with NIH(OR=0.772, 95%CI=0.772~0.992).5.Dichotomy analysis showed that rs1049216, rs6948, rs2227310, rs12415607 all have interaction with educational level and sleep duration,while rs1127687 showed interaction with using headphones and making phone call. The individuals with(AG+AA)genotypes and wearing headphones, call time ≧16(min/d) are significantly increased risk of NIHL(OR=2.008, 95%CI=1.174~3.434;OR= 2.283,95%C=1.265~4.122) compared to those who have GG genotype and do not wear headphones, call time<16(min/d).rs1049216 respectively with rs6948, rs2227310, rs12415607 showed significantly gene-gene interaction,so rs6948 with rs2227310, rs12415607.when its genetic variants exist together, can significantly reduce the risk of NIHL.Conclusions: Our findings verified the imporant influence of environmental factors on NIHL risk.There was the correlation between CASP3,CASP7 polymorphisms and NIHL in Chinese Han population.Synergism was also observed between genotype and environmental factors.Further studies with large sample size are warranted to validate our findings.