Background

In 2012, the International Agency for Research on Cancer (IARC) concluded that diesel engine emissions (DEE) emissions cause cancer in humans. However, there is still controversy surrounding this conclusion, due to several studies since the IARC decision citing a lack of evidence of a dose-response relationship.

Objectives

Through a systematic review, we aimed to evaluate all evidence on the association between occupational DEE and lung cancer to investigate whether there is an increased risk of lung cancer for workers exposed to DEE and if so, to describe the dose-response relationship.

Methods

We registered the review protocol with PROSPERO and searched for observational studies in relevant literature databases. Two independent reviewers screened the studies’ titles/abstracts and full texts, and extracted and assessed their quality. Studies with no direct DEE measurement but with information on length of exposure for high-risk occupations were assigned exposure values based on the DEE Job-Exposure-Matrix (DEE-JEM). After assessing quality and informativeness, we selected appropriate studies for the dose-response meta-analysis.

Results

Sixty-five reports (from thirty-seven studies) were included in the review; one had a low risk of bias (RoB) (RR per 10 μg/m³-years: 1.014 [95%CI 1.007–1.021]). There was an increased, statistically significant risk of lung cancer with increasing DEE exposure for all studies (RR per 10 μg/m³-years = 1.013 [95%CI 1.004–1.021]) as well as for studies with a low RoB in the exposure category (RR per 10 μg/m³-years = 1.008 [95% CI1.001–1.015]). We obtained a doubling dose of 555 μg/m³-years for all studies and 880 μg/m³-years for studies with high quality in the exposure assessment.

Discussion

We found a linear positive dose-response relationship for studies with high quality in the exposure domain, even though all studies had an overall high risk of bias. Current threshold levels for DEE exposure at the workplace should be reconsidered.

中文翻译：

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柴油发动机排放物职业暴露与肺癌风险之间的剂量反应关系：系统评价和荟萃分析

背景

2012年，国际癌症研究机构(IARC)得出结论，柴油发动机排放物(DEE)排放会导致人类癌症。然而，由于自 IARC 决定以来的几项研究指出缺乏剂量反应关系的证据，围绕这一结论仍存在争议。

目标

通过系统评价，我们旨在评估职业性 DEE 与肺癌之间关联的所有证据，以调查接触 DEE 的工人患肺癌的风险是否增加，如果是，则描述剂量反应关系。

方法

我们在 PROSPERO 注册了审查方案，并在相关文献数据库中检索了观察性研究。两名独立评审员筛选了研究的标题/摘要和全文，并提取和评估其质量。没有直接 DEE 测量但包含高风险职业暴露时间长度信息的研究根据 DEE 工作暴露矩阵 (DEE-JEM) 分配暴露值。在评估质量和信息量后，我们选择了适当的研究进行剂量反应荟萃分析。

结果

审查中纳入了 65 份报告（来自 37 项研究）；其中一项的偏倚风险 (RoB) 较低（每 10 μg/m ³年的 RR：1.014 [95%CI 1.007–1.021]）。^{所有研究（每 10 μg/m 3}年的 RR = 1.013 [95%CI 1.004–1.021]）以及 RoB 较低的研究中，随着 DEE 暴露的增加，患肺癌的风险也增加，具有统计学意义。暴露类别（每 10 μg/m ³年的 RR = 1.008 [95% CI1.001–1.015]）。我们在所有研究中获得了 555 μg/m ³年的双倍剂量，在暴露评估中高质量的研究中获得了 880 μg/m ^{3年的双倍剂量。}

讨论

我们发现暴露领域的高质量研究存在线性正剂量反应关系，尽管所有研究总体上都存在较高的偏倚风险。应重新考虑当前工作场所 DEE 暴露的阈值水平。