Association between hearing protection device use and noise-induced hearing loss among manufacturing workers in China: a cross-sectional study

Objective: Noise-induced hearing loss (NIHL) is a leading occupational illness globally. This study aimed to identify factors related to hearing protection device (HPD) use that were associated with NIHL and to quantify the relationship between the duration of HPD use and NIHL risk. Methods: In a cross-sectional study, 845 noise-exposed manufacturing workers in China underwent health examinations and surveys. The associations between hearing protection devices use duration, related factors, and hearing loss were analyzed using multivariable linear regression and restricted cubic spline model. Results: Providing hearing protection and training in its use at the enterprise level were associated with less hearing loss. At the individual level, consistent full-day use of hearing protection and using earplugs instead of earmuffs were linked to significantly less hearing loss. Lower hearing thresholds were linked to longer HPD use: each additional year of use was associated with a modest (~0.3 dB) reduction in the increase of hearing thresholds. Greater protective associations were observed after approximately 3 years of continuous use. Conclusion: Longer duration of HPD use is associated with milder hearing loss, particularly among workers reporting sustained use for three or more years, underscoring the importance of long-term hearing protection in noisy workplaces.