Objective To explore the correlation between CASP3 gene polymorphism and the risk of noise-induced hearing loss (NIHL).

Methods Noise-exposed workers from an automobile manufacturing plant with an 8-hour equivalent noise level ≥ 80 dB (A) were selected for this study. A total of 173 workers diagnosed with NIHL were assigned to the case group. Meanwhile, 170 workers with normal hearing from the same or adjacent workstations were selected as the control group, matched for age, noise exposure duration, and noise intensity levels. The MassArray system was used to detect the genotype of the CASP3 gene at the rs1049216 and rs1405937 loci. Multivariate logistic regression was used to analyze the relationship between CASP3 gene polymorphism and the risk of NIHL.

Results There was a statistically significant difference in the genotype frequencies of GG, GA, and AA at the CASP3 rs1049216 locus between these two groups (P < 0.05), while there was no statistically significant difference in the allele frequencies of G and A (P=.84). Multivariable logistic regression analysis showed that, after controlling for confounding factors such as age, years of service, smoking, drinking, educational level, and noise exposure intensity, workers with the AA genotype at rs1049216 had a lower risk of developing NIHL than those with the GG genotype (OR=0.23, 95%CI=0.06 to 0.85, P < 0.05). Workers with the GG + GA genotypes had a higher risk of NIHL than those with the AA genotype (OR=4.87, 95%CI=1.32 to 17.98, P < 0.05). No statistically significant differences in NIHL risk were observed among genotypes at rs1405937 between the two groups (P>0.05).

Conclusions The rs1049216 gene polymorphism is associated with susceptibility to NIHL, and the GG and GG + GA genotypes may be risk factors for NIHL.