Comprehensive Effect of Environmental Noise Exposure on Trouble Sleeping: Mediating Roles of Tinnitus, Hearing Loss and Mental Illnesses

Background: Environmental noise exposure, tinnitus and hearing loss (HL) are hypothesised to influence trouble sleeping, but their integrated effects and mediating pathways remain unclear. This study evaluates associations amongst noise exposure, auditory health and sleep outcomes and explores mediation by tinnitus and HL. Methods: A total of 8539 participants were enrolled using data from the National Health and Nutrition Examination Survey (NHANES, 2006–2020). Logistic regression and mediation analysis examined associations amongst noise exposure, auditory health and sleep outcomes. Results: Noise exposure (workplace: adjusted odds ratio [OR] = 1.145, 95% confidence interval [CI]: 1.015–1.292, P = 0.027; off-work: adjusted OR = 1.165, 95% CI: 1.005–1.348, P = 0.042) and tinnitus (adjusted OR = 1.648, 95% CI: 1.442–1.882, P < 0.001) were positively associated with trouble sleeping, and speech-frequency HL (SFHL) showed a protective effect (adjusted OR = 0.767, 95% CI: 0.660–0.891, P = 0.001). The association between noise exposure and trouble sleeping was significantly mediated by tinnitus and depression (accounting for 12.76%–37.80% of total effects) but not by SFHL. Subgroup analyses showed that SFHL was only significantly associated with trouble sleeping in the subgroups of those unexposed to a noise environment, whereas tinnitus was significant in each subgroup. Restricted cubic spline analyses showed that hearing thresholds ≥20 dB were linked to reduced risk of trouble sleeping, with nonlinear (inverted U-shaped) trends in the subgroups of noise-exposed workplace and noise-unexposed off-work. Conclusions: > Workplace and off-work noise exposures are closely associated with trouble sleeping, with tinnitus mediating this association and SFHL exerting a protective effect. The findings highlight the importance of controlling noise exposure and implementing preventive interventions for tinnitus to alleviate noise-related sleep issues.