Department of Systems Engineering and Management, Air Force Institute of Technology, Wright-Patterson AFB, Ohio.
Environmental Health Effects Laboratory, Naval Medical Research Unit Dayton, Wright-Patterson AFB, Ohio.
J Occup Environ Hyg. 2021 Jul;18(7):323-333. doi: 10.1080/15459624.2021.1922693. Epub 2021 Jun 8.
Noise exposure has traditionally been considered the primary risk factor for hearing loss. However, ototoxicants commonly found in occupational settings could affect hearing loss independently, additively, or synergistically when combined with noise exposures. The purpose of this investigation was to determine the combined effect of metal and solvent ototoxicants, continuous noise, and impulse noise on hearing loss. Noise and ototoxicant exposure and pure-tone audiometry results were analyzed for U.S. Air Force personnel (n = 2,372) at a depot-level aircraft maintenance activity at Tinker Air Force Base, Oklahoma. Eight similar exposure groups based on combinations of ototoxicant and noise exposure were created including: (1) Continuous noise (reference group); (2) Continuous noise + Impulse noise; (3) Metal exposures + Continuous noise; (4) Metal exposures + Continuous noise + Impulse noise; (5) Solvent exposure + Continuous noise; (6) Solvent exposures + Continuous noise + Impulse noise; (7) Metal exposure + Solvent exposures + Continuous noise; and (8) Metal exposure + Solvent exposures + Continuous noise + Impulse noise. Hearing loss was assessed at center octave band frequencies of 500-6,000 Hz and using National Institute for Occupational Safety and Health Standard Threshold Shift (STS) criteria. Hearing changes were significantly worse at 2,000 Hz in the Metal exposure + Solvent exposure + Continuous noise group compared to the Continuous noise only reference group (p = 0.023). The Metal exposure + Solvent exposure + Continuous noise group had a significantly greater relative risk (RR) of 2.44; 95% CI [1.24, 4.83] for developing an STS at 2,000 Hz. While not statistically significant, the Solvent exposure + Continuous noise group had a RR of 2.32; 95%CI [1.00, 5.34] for developing an STS at 1,000 Hz. These results indicate that noise exposure may dominate hearing loss at ≥3,000 Hz while combined effects of concomitant exposure to ototoxic substances and noise are only noticeable at ≤2,000 Hz. These results also suggest combined exposures to ototoxicants and noise presents a greater hearing loss risk than just noise.
噪声暴露一直被认为是听力损失的主要危险因素。然而，职业环境中常见的耳毒性物质可能会独立地、附加地或协同地影响听力损失，当与噪声暴露结合时。本研究的目的是确定金属和溶剂耳毒性物质、连续噪声和脉冲噪声对听力损失的综合影响。对俄克拉荷马州廷克空军基地飞机维修基地的美国空军人员（n=2372）的噪声和耳毒性物质暴露以及纯音测听结果进行了分析。根据耳毒性物质和噪声暴露的组合，创建了 8 个类似的暴露组，包括：（1）连续噪声（参考组）；（2）连续噪声+脉冲噪声；（3）金属暴露+连续噪声；（4）金属暴露+连续噪声+脉冲噪声；（5）溶剂暴露+连续噪声；（6）溶剂暴露+连续噪声+脉冲噪声；（7）金属暴露+溶剂暴露+连续噪声；（8）金属暴露+溶剂暴露+连续噪声+脉冲噪声。听力损失在 500-6000Hz 的中心倍频程频率处进行评估，并使用国家职业安全与健康研究所标准阈值移位（STS）标准进行评估。与仅连续噪声的参考组相比，金属暴露+溶剂暴露+连续噪声组在 2000Hz 时听力损失明显更差（p=0.023）。金属暴露+溶剂暴露+连续噪声组在 2000Hz 时发生 STS 的相对风险（RR）显著增加 2.44；95%CI[1.24，4.83]。虽然没有统计学意义，但溶剂暴露+连续噪声组在 1000Hz 时发生 STS 的 RR 为 2.32；95%CI[1.00，5.34]。这些结果表明，噪声暴露可能在≥3000Hz 时主导听力损失，而同时接触耳毒性物质和噪声的联合效应仅在≤2000Hz 时才明显。这些结果还表明，与噪声相比，同时接触耳毒性物质和噪声会增加听力损失的风险。
