Reduced lung cancer mortality and exposure to synthetic fluids and biocide in the auto manufacturing industry
Reduced lung cancer mortality and exposure to synthetic fluids and biocide in the auto manufacturing industry
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DOI：
10.5271/sjweh.3088
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发表时间：
2010-11-01
影响因子：
6.3
通讯作者：
Eisen, Ellen A.
中科院分区：
文献类型：
--
作者：
Mehta, Amar J.;Malloy, Elizabeth J.;Eisen, Ellen A.
目的汽车制造中使用的水溶性和合成金属加工液（MWF）可能受到革兰氏阴性菌内毒素的污染，而革兰氏阴性菌内毒素是一种可能的抗癌物质。通常用于限制细菌生长的杀菌剂的有效性尚不清楚。我们调查了肺癌与合成MWF和杀菌剂（作为内毒素暴露的替代品）之间的负相关关系是否在汽车工人的长期随访中持续存在。方法对46399名汽车制造业工人进行回顾性队列研究，采用巢式病例对照分析。后续工作于1941年开始，并从1985年延长至1995年。在Cox回归模型中，肺癌的死亡率比率（MRR）作为累积暴露于合成MWF （mg/m(3) /年）和暴露于含有合成和可溶性MWF的杀菌剂的年数的离散和平滑函数进行估计。该分析也仅限于1941年或之后雇用的亚队列，并按随访期分层。结果样条曲线显示肺癌死亡率随内毒素暴露量的增加呈非线性逆暴露反应。总体而言，在暴露的第99（th）百分位数（每年15.8 mg/m(3)）时，在暴露最高的人群中观察到死亡率的最大降低[MRR 0.63, 95%可信区间（95% CI） 0.39-0.98]。相反效果的证据仅限于早期随访期。杀菌剂对效果的改善有统计学意义（P=0.07）；合成MWF的保护作用仅对那些共同暴露的人观察到。结论：合成MWF对肺癌死亡率的保护作用虽然减弱，但在长期随访中持续存在，并且仅在同时暴露于杀菌剂和合成MWF的工人中观察到。
Objectives Water-based soluble and synthetic metalworking fluids (MWF) used in auto manufacturing may be contaminated by endotoxin from Gram-negative bacteria, a possible anticarcinogen via increased immuno-surveillance. The effectiveness of biocide, generally added to limit bacterial growth is unknown. We investigated whether an inverse relationship between lung cancer and synthetic MWF and biocide - as surrogates of endotoxin exposure - persisted in an extended follow-up of autoworkers.Methods A nested case control analysis was performed within a retrospective cohort study of 46 399 auto manufacturing workers. Follow-up began in 1941 and was extended from 1985-1995. Mortality rate ratios (MRR) were estimated in Cox regression models for lung cancer as discrete and smoothed functions of cumulative exposure to synthetic MWF (mg/m(3) per year) and years exposed to biocide with both synthetic and soluble MWF. The analysis was also restricted to the subcohort hired on or after 1941 and stratified by follow-up period.Results The splines suggested a non-linear inverse exposure response for lung cancer mortality with increasing endotoxin exposure. Overall, the greatest reduction in mortality was observed among those with the highest exposure [MRR 0.63, 95% confidence interval (95% CI) 0.39-0.98] at the 99(th) percentile of exposure (15.8 mg/m(3) per year). Evidence for an inverse effect was limited to the earlier follow-up period. Effect modification by biocide was marginally significant (P=0.07); the protective effect of synthetic MWF was observed only for those who were co-exposed.Conclusions The protective effect of synthetic MWF against lung cancer mortality persisted through the extended period of follow-up, although attenuated, and was observed only among workers with co-exposure to biocide and synthetic MWF.