Objective To assess the relationship among occupational noise exposure, hematological inflammation markers, and blood pressure of noise-exposed workers.

Methods In 2024, a total of 847 workers from a piano manufacturing enterprise in Guangdong Province were selected as study participants. Noise levels at different worksites were measured, and participants were categorized into three groups based on their occupational noise exposure levels, namely non-occupationally exposed, 80 - 85 dB(A), and ≥ 85 dB(A). Demographic characteristics, personal lifestyle factors, and occupational information were collected via structured questionnaires. Blood samples were taken to assess routine hematological parameters, and blood pressure measurements were obtained. Multiple linear regression models were used to evaluate the impact of occupational noise exposure on blood pressure and inflammatory markers. The mediating effects of inflammation on the association between noise exposure and blood pressure were analyzed using the bootstrap sampling method.

Results Occupational noise exposure was positively associated with neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and aggregate index of systemic inflammation (AISI), and negatively associated with lymphocyte-to-monocyte ratio (LMR) (all P < 0.01). Multivariate linear regression analysis (after natural logarithmic transformation) showed that: (1) Compared with the non-occupationally exposed group, the systolic and diastolic blood pressures of workers of the noise exposure ≥ 85 dB(A) group were increased by 0.030 mmHg and 0.047 mmHg, respectively (both P < 0.05); (2) For each unit increase in LMR, systolic and diastolic blood pressures rose by 0.052 mmHg and 0.065 mmHg, respectively (both P < 0.05); for each unit increase in AISI, systolic and diastolic blood pressures increased by 0.038 mmHg and 0.052 mmHg, respectively (both P < 0.05). The bootstrap-based mediation analysis revealed that: (1) Compared to the non-occupationally exposed group, the mediating effects of PLR on the relationship between noise exposure and systolic blood pressure were 26.25% and 43.80% in the groups of workers with noise exposure between 80 - 85 dB(A) and ≥ 85 dB(A), respectively; the mediating effects on diastolic blood pressure were 30.66% and 34.93%, respectively; (2) The mediating effects of AISI on the association between noise exposure and diastolic blood pressure were 16.56% and 30.12% in the 80 - 85 dB(A) and ≥ 85 dB(A) groups, respectively.

Conclusions Occupational noise exposure may lead to elevated systemic inflammatory markers and increased blood pressure. Inflammatory indices such as PLR and AISI may serve as potential mediators in the pathway linking noise exposure to elevated blood pressure.