Department of Systems Engineering and Management, Air Force Institute of Technology, Wright-Patterson AFB, Ohio, USA.
Safety and Environmental Section, 3d Marine Logistics Group, Camp Kinser, Okinawa, Japan.
Ear Hear. 2022;43(4):1291-1299. doi: 10.1097/AUD.0000000000001178. Epub 2021 Dec 2.
The purpose of this retrospective cohort study was to compare the relative risks (RR) of hearing impairment due to co-exposure of continuous noise, impulse noise, metal ototoxicants, and organic solvent ototoxicants using several pure tone audiometry (PTA) evaluation methods.
Noise and ototoxicant exposure and PTA records were extracted from a DoD longitudinal repository and were analyzed for U.S. Air Force personnel (n = 2372) at a depot-level aircraft maintenance activity at Tinker Air Force Base, Oklahoma using an historical cohort study design. Eight similar exposure groups based on combinations of ototoxicant and noise exposure were created: (1) Continuous noise (reference group); (2) Continuous noise + Impulse noise; (3) Metal exposure + Continuous noise; (4) Metal exposure + Continuous noise + Impulse noise; (5) Solvent exposure + Continuous noise; (6) Solvent exposure + Continuous noise + Impulse noise; (7) Metal exposure + Solvent exposure + Continuous noise; and (8) Metal exposure + Solvent exposure + Continuous noise + Impulse noise. RR of hearing impairment compared to the Continuous noise-exposed reference group was assessed with five PTA evaluation methods including (1) U.S. Department of Defense (DoD) Significant Threshold Shift (STS), (2) Occupational Safety and Health Administration (OSHA) age-adjusted STS, (3) National Institute for Occupational Safety and Health (NIOSH) STS, (4) NIOSH Material Hearing Impairment, and (5) All Frequency Threshold Average.
Hearing impairment was significantly worse for SEG (2) combined exposure to continuous noise and impulse noise only for the PTA evaluation method (2) OSHA Age Adjusted with an RR of 3.11, [95% confidence interval (CI), 1.16-8.31] and was nearly significantly different using PTA evaluation method (4) NIOSH Material Hearing Impairment with an RR of 3.16 (95% CI, 0.99-10.15). Despite no significant differences for SEGs with an ototoxicant exposure, PTA evaluation method (3) NIOSH STS was most sensitive in detecting hearing changes for SEG (8) Metal exposure + Solvent exposure + Continuous noise + Impulse noise as demonstrated by a RR of 1.12 (95% CI, 0.99-1.27).
Results suggest that a single PTA evaluation technique may not be adequate in fully revealing hearing impairment risk due to all stressors and tailoring the PTA evaluation technique to the hazards present in the workplace could better detect hearing impairment. Additionally, results suggest that PTA may not be effective as the sole technique for evaluating hearing impairment due to ototoxicant exposure with continuous noise co-exposure.
本回顾性队列研究的目的是比较因连续噪声、脉冲噪声、金属耳毒性剂和有机溶剂耳毒性剂共同暴露而导致听力损伤的相对风险（RR），使用几种纯音听阈（PTA）评估方法。
噪声和耳毒性剂暴露以及 PTA 记录从国防部纵向存储库中提取，并使用历史队列研究设计在俄克拉荷马州廷克空军基地的一个机库级飞机维修活动中对美国空军人员（n=2372）进行分析。根据耳毒性剂和噪声暴露的组合，创建了八个类似的暴露组：（1）连续噪声（参照组）；（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；和（8）金属暴露+溶剂暴露+连续噪声+脉冲噪声。使用五种 PTA 评估方法评估与连续噪声暴露参照组相比听力损伤的 RR，包括（1）美国国防部（DoD）显著阈移（STS）；（2）职业安全与健康管理局（OSHA）年龄调整 STS；（3）国家职业安全与健康研究所（NIOSH）STS；（4）NIOSH 材料听力损伤；和（5）所有频率阈值平均。
仅对于 PTA 评估方法（2）OSHA 年龄调整，联合暴露于连续噪声和脉冲噪声的 SEG（2）听力损伤明显更差，RR 为 3.11[95%置信区间（CI），1.16-8.31]，而使用 PTA 评估方法（4）NIOSH 材料听力损伤时，RR 接近 3.16（95%CI，0.99-10.15）。尽管 SEG 中接触耳毒性剂无显著差异，但 PTA 评估方法（3）NIOSH STS 最能检测到 SEG（8）金属暴露+溶剂暴露+连续噪声+脉冲噪声的听力变化，RR 为 1.12（95%CI，0.99-1.27）。
结果表明，由于所有应激源，单一的 PTA 评估技术可能不足以充分揭示听力损伤风险，并且根据工作场所存在的危害定制 PTA 评估技术可能会更好地检测听力损伤。此外，结果表明，由于连续噪声共同暴露，PTA 可能不是评估接触耳毒性剂所致听力损伤的唯一有效技术。
