Sbihi Hind, Teschke Kay, MacNab Ying C, Davies Hugh W
School of Environmental Health, University of British Columbia, 2206 East Mall, Vancouver, British Columbia, Canada V6T 1Z3.
Ann Occup Hyg. 2010 Apr;54(3):329-39. doi: 10.1093/annhyg/meq001. Epub 2010 Mar 17.
To account for use of hearing protection devices (HPDs) in retrospective noise exposure assessment, adjust noise exposure estimates accordingly, and validate the adjusted estimates.
A previous study in the same working population showed a stronger relation for noise and acute myocardial infarction among those who did not wear HPD. Because accurate noise exposure assessment is complicated by the use of HPD, we previously developed a multilevel model of the likelihood of HPD use for British Columbia (Canada) lumber mill workers. Historical estimates of noise exposure can be adjusted according to models predictions and a reduction in misclassifying workers, exposure is expected.
Work history and exposure information were obtained for 13,147 lumber mill workers followed from 1909 until 1998. Audiometric data for the cohort, including hearing threshold levels at several pure tone frequencies, were obtained from the local regulatory agency for the period from 1978 to 2003. Following the modeling of HPD use, noise estimates were adjusted according to models predictions and attenuation factors based on existing research and standards. Adjusted and unadjusted noise metrics were compared by investigating their ability to predict noise-induced hearing loss.
We showed a 4-fold increase in the noise exposure and hearing loss slope, after adjusting for HPD use, while controlling for gender, age, race, as well as medical and non-occupational confounding variables.
While the relative difference before and after adjustment for use of HPD is considerable, we observed a subtle absolute magnitude of the effect. Using noise-induced hearing loss as a 'gold standard' for testing the assessment of retrospective noise exposure estimates should continue to be investigated.
在回顾性噪声暴露评估中考虑听力保护装置（HPD）的使用情况，相应地调整噪声暴露估计值，并验证调整后的估计值。
之前针对同一工作人群的一项研究表明，在未佩戴HPD的人群中，噪声与急性心肌梗死之间的关联更强。由于HPD的使用使准确的噪声暴露评估变得复杂，我们之前为加拿大不列颠哥伦比亚省的木材厂工人开发了一个HPD使用可能性的多层次模型。可以根据模型预测调整噪声暴露的历史估计值，预计会减少对工人暴露情况的错误分类。
获取了1909年至1998年期间跟踪的13147名木材厂工人的工作史和暴露信息。该队列的听力测定数据，包括几个纯音频率下的听力阈值水平，是从当地监管机构获取的1978年至2003年期间的数据。在对HPD使用情况进行建模后，根据模型预测以及基于现有研究和标准的衰减因子调整噪声估计值。通过研究调整后和未调整后的噪声指标预测噪声性听力损失的能力来进行比较。
在控制了性别、年龄、种族以及医疗和非职业性混杂变量后，我们发现调整HPD使用情况后，噪声暴露与听力损失斜率增加了4倍。
虽然调整HPD使用前后的相对差异相当大，但我们观察到效应的绝对幅度较小。以噪声性听力损失作为“金标准”来检验回顾性噪声暴露估计值的评估仍需继续研究。
