Molecular genetic markers of early development of occupational sensorineural hearing loss

Introduction. Occupational sensorineural hearing loss (OSNHL) is one of the most common occupational diseases. Individual genetic predisposition can determine the variability in the timing of its development in workers exposed to industrial noise.The study aims to evaluate the effect of polymorphic variants of the MTHFR (rs1801133, C677T) and ApoE (ε2, ε3, ε4) genes on the development of occupational sensorineural hearing loss.Materials and methods. The authors examined 237 men: 152 patients with a diagnosis of occupational sensorineural hearing loss (the main group) and 85 employees of noise-hazardous professions without hearing impairment (the reference group). The main group was stratified into two subgroups, depending on the length of service prior to diagnosis: with early (less than 15 years, n=49) and late (more than 15 years, n=73) disease development. The specialists genotyped polymorphisms using PCR followed by the analysis of restriction products. They performed statistical analysis in the RStudio environment (version 1.2.1335).Results. It was found that carriage of the homozygous CC genotype by the C677T polymorphism of the MTHFR gene is associated with early development of occupational sensorineural hearing loss (OR=4.459; 95% CI: 1.935–10.737; p<0.001). The heterozygous CT genotype demonstrated a protective effect against the early development of the disease. Carriage of the ε4 allele of the ApoE gene was also associated with a reduction in the latent period of development of occupational sensorineural hearing loss (OR=0.355; 95% CI: 0.122–0.982; p=0.033). Arterial hypertension was significantly more common among carriers of the CC genotype of the MTHFR gene (p<0.05). The data obtained indicate a significant role of genetic polymorphisms in the pathogenesis of occupational sensorineural hearing loss. The determination of the MTHFR (C677T) and ApoE genotypes can be used to identify groups at increased risk of early development of hearing loss in order to implement preventive measures.Limitations. Limited sampling and geographical specificity, the study was conducted only on a sample from Novosibirsk, which may limit the applicability of the results to other regions and ethnic groups. The genetic homogeneity of the study group may influence the associations found and their interpretation. The study does not include long-term monitoring of disease progression. The methods of genotyping and statistical analysis used in the study have their limitations in accuracy and sensitivity. Possible errors in genotyping and data analysis may affect the results and their interpretation.Conclusion. The carriage of the homozygous CC genotype by the polymorphic variant C677T of the MTHFR gene and the ε4 allele of the ApoE gene is a marker of an increased risk of early development of occupational sensorineural hearing loss in people working under the influence of industrial noise.Ethics. The study was conducted in compliance with all ethical principles of medical research, with the voluntary informed consent of patients. The ethical aspects of the study were reviewed and approved by the local Ethics Committee (LNEC Protocol No. 5 dated September 2, 2025).Contributions:Poteryaeva E.L. — research concept and design, collecting research material, writing the text of the manuscript, editing the text of the manuscript;Funtikova I.S. — research concept and design, collection of research material, writing of the manuscript text;Smirnova E.L. — research concept and design, review of publications on the topic of the article, editing the text of the manuscript;Maksimov V.N. — editing the text of the manuscript, researching concept and design;Savchenko O.A. — writing the text of the manuscript, reviewing publications on the topic of the article, editing the text of the manuscript;Fedorova I.A. — review of publications on the subject of the article.Funding. The study had no funding.Conflict of interest. The authors declare no conflict of interest.Received: 07.12.2025 / Accepted: 16.02.2026 / Published: 27.03.2026