Lifetime Noise Exposure and Its Interaction With Ageing: Effects on Audiometric Thresholds, Speech-In-Noise...

Noise-induced and age-related hearing loss involve partially similar pathophysiology, but their combined effects remain poorly understood, especially in under-regulated occupational settings. This study investigated the independent and interaction effects of lifetime noise exposure and age on audiometric, speech-in-noise, and tinnitus outcomes in Palestinian workers. Ninety-eight adult workers aged 18 - 75 years completed standard (0.25 - 8 kHz) and extended high-frequency (10 - 14 kHz) audiometry, Arabic diotic and antiphasic digits-in-noise (DIN) testing, and an Arabic Noise Exposure Structured Interview. Regression models tested age × noise interactions, adjusting for sex (and education for DIN), with Bonferroni-Holm correction applied for multiple comparisons. The protocol was pre-registered (Open Science Framework; https://osf.io/v2c9z). There was no significant age × noise interaction for standard audiometric thresholds (3 - 8 kHz; β = 0.23 dB/year per log₁₀[noise], 95% CI 0.03 - 0.42; p = 0.02), after correction for multiple comparisons. Age-stratified analyses showed greater exposure was associated with worse standard audiometric thresholds in older adults (≥44 years; β = 8.1 dB per 10-fold increase, 95% CI 2.5 - 13.6; p = 0.005) but not younger adults. No interaction or main effects of noise were observed for extended high-frequency thresholds, DIN, or tinnitus (p > 0.05). Age was significantly associated with standard and extended high-frequency audiometric thresholds and diotic and antiphasic DIN thresholds. Auditory outcomes were primarily age-driven, with limited noise effects. Greater noise-related threshold loss appeared in older adults, but age effects were larger, suggesting ageing as the dominant determinant. Hearing conservation should address age-related vulnerability alongside exposure control.