Retrospective cohort study of pure tone audiometry hearing changes from ototoxic metals and solvents, continuous noise and impulse noise exposures at Robins Air Force Base from 2005 to 2019

A retrospective study of continuous noise, impulse noise, heavy metals, and solvent exposure and pure-tone audiometry data on Robins AFB (RAFB) personnel investigated the relative risk (RR) of hearing loss, using a noise-only control group from a Hill AFB study. There were significant RRs for continuous noise + impulse noise + heavy metals (RR = 4.90, 95% CI: 1.81-13.25, 500 Hz, left ear; RR = 4.45, 95% CI: 1.41-14.10, 1,000 Hz, left ear), and continuous noise + impulse noise (RR = 2.77, 95% CI: 1.06-7.24, 1,000 Hz, left ear). Conversely, there was a protective effect at 4,000 Hz for continuous noise + impulse noise (RR = 0.51, 95% CI: 0.35 - 0.74, left ear; RR = 0.68, 95% CI: 0.46-0.99, right ear) and continuous noise + impulse noise + ototoxic solvents (RR = 0.38, 95% CI: 0.17-0.86, left ear).