Objective To investigate the adverse effects of occupational noise exposure on the immune function of noise-exposed workers.

Methods A cluster sampling method was used to recruit 65 workers in Guangdong Province who were identified as having suspected occupational noise-induced hearing loss during on-the-job occupational health examinations during March 2019 and March 2020. Based on the presence or absence of tinnitus symptoms, participants were divided into a tinnitus group (n = 35) and a non-tinnitus group (n = 30). An additional 45 individuals without occupational noise exposure were selected as the control group. Venous blood samples were collected from all participants under a resting supine state in the morning fasting time to measure T lymphocyte subsets, immunoglobulins (IgG, IgM, and IgA), and complement components (C3 and C4). Intergroup differences in these immune indicators were analyzed.

Results Compared to the control group, there were no statistically significant differences in the levels of CD3⁺ T cells, CD3⁺CD4⁺ T cells, CD3⁺CD8⁺ T cells, or the CD3⁺CD4⁺/CD3⁺CD8⁺ T cell ratio in either the tinnitus or non-tinnitus groups (all P > 0.05). However, the IgM level in the tinnitus group was significantly lower than that in the control group (P < 0.05), and the C3 levels in both the tinnitus and non-tinnitus groups were significantly higher than those in the control group (P < 0.05). No other significant differences were observed among the three groups (P > 0.05).

Conclusions Occupational noise exposure may affect the humoral and innate immune systems of workers but have no impact on the cellular immune system.