Center for Health Sciences, Exponent, Inc., Menlo Park, California.
Stanford Cancer Institute, Stanford, California.
Am J Epidemiol. 2018 Jun 1;187(6):1210-1219. doi: 10.1093/aje/kwy038.
The Diesel Exhaust in Miners Study (DEMS) (United States, 1947-1997) reported positive associations between diesel engine exhaust exposure, estimated as respirable elemental carbon (REC), and lung cancer mortality. This reanalysis of the DEMS cohort used an alternative estimate of REC exposure incorporating historical data on diesel equipment, engine horsepower, ventilation rates, and declines in particulate matter emissions per horsepower. Associations with cumulative REC and average REC intensity using the alternative REC estimate and other exposure estimates were generally attenuated compared with original DEMS REC estimates. Most findings were statistically nonsignificant; control for radon exposure substantially weakened associations with the original and alternative REC estimates. No association with original or alternative REC estimates was detected among miners who worked exclusively underground. Positive associations were detected among limestone workers, whereas no association with REC or radon was found among workers in the other 7 mines. The differences in results based on alternative exposure estimates, control for radon, and stratification by worker location or mine type highlight areas of uncertainty in the DEMS data.
矿工柴油机排气研究（DEMS）（美国，1947-1997 年）报告了柴油机排气暴露与肺癌死亡率之间的正相关关系，柴油机排气暴露通过可吸入元素碳（REC）来估计。本研究使用包含柴油机设备、发动机马力、通风率以及每马力颗粒物排放量下降的历史数据的替代 REC 暴露估计值，重新分析了 DEMS 队列。与原始 DEMS REC 估计值相比，使用替代 REC 估计值和其他暴露估计值的累积 REC 和平均 REC 强度的关联普遍减弱。大多数发现没有统计学意义；控制氡暴露大大削弱了与原始和替代 REC 估计值的关联。在仅在地下工作的矿工中，未发现与原始或替代 REC 估计值的关联。在石灰石工人中检测到了正相关，而在其他 7 个矿的工人中未发现 REC 或氡与矿工之间的关联。基于替代暴露估计值、控制氡以及按工人位置或矿山类型分层的结果差异突出了 DEMS 数据中的不确定性领域。
