Effects of air pollution and noise exposure on occupational hearing loss in oil workers: a prospective cohort study.

BACKGROUND

Occupational Hearing Loss (OHL) is a significant health concern among oil workers, influenced by environmental and occupational factors. This study investigates the independent and synergistic effects of air pollution and noise exposure on OHL risk in this high-risk population.

METHODS

A prospective cohort study included 1,179 oil workers from Hebei Province, China, with baseline data (2017-2019) and follow-up until 2023. Air pollution exposure (PM, PM, SO, NO, CO, and the Air Quality Comprehensive Index, AQCI) was assessed using monitoring station data, while cumulative noise exposure (dB(A)-year) was calculated from workplace measurements. Multivariable-adjusted Modified Poisson regression and Restricted Cubic Splines (RCS) analyzed associations and dose-response relationships.

RESULTS

The OHL incidence was 34.5% (n = 407). Air pollutants exhibited significant nonlinear associations with OHL: PM showed a U-shaped curve, SO an inverted U-shape, and NO an S-shaped curve. Noise exposure ≥ 85 dB(A)-year tripled OHL risk (Relative Risk, RR = 2.361, Confidence Interval, 95%CI: 1.861-2.994). Synergistic effects were robust for AQCI (RR = 5.776, 95%CI:3.225-10.345) and NO (RR = 4.297, 95%CI:1.879-9.825) with high noise exposure, while PM demonstrated antagonistic effects.

CONCLUSIONS

Air pollution and noise exposure independently and synergistically increase OHL risk in oil workers. AQCI and NO, combined with noise, are critical risk factors. These findings underscore the need for integrated exposure monitoring, optimized ventilation, and enhanced personal protective measures in high-risk occupational settings.