Steenland Kyle, Barry Vaughn, Anttila Ahti, Sallmén Markku, McElvenny Damien, Todd A C, Straif Kurt
Rollins School PubHealth, Emory University, Atlanta, USA.
Finnish Cancer Registry, Helsinki, Finland.
Occup Environ Med. 2017 Nov;74(11):785-791. doi: 10.1136/oemed-2017-104311. Epub 2017 May 25.
To investigate further whether inorganic lead is a carcinogen among adults, or associated with increased blood pressure and kidney damage, via a large mortality study.
We conducted internal analyses via Cox regression of mortality in three cohorts of lead-exposed workers with blood lead (BL) data (USA, Finland, UK), including over 88 000 workers and over 14 000 deaths. Our exposure metric was maximum BL. We also conducted external analyses using country-specific background rates.
The combined cohort had a median BL of 26 µg/dL, a mean first-year BL test of 1990 and was 96% male. Fifty per cent had more than one BL test (mean 7). Significant (p<0.05) positive trends, using the log of each worker's maximum BL, were found for lung cancer, chronic obstructive pulmonary disease (COPD), stroke and heart disease, while borderline significant trends (0.05≤p≤0.10) were found for bladder cancer, brain cancer and larynx cancer. Most results were consistent across all three cohorts. In external comparisons, we found significantly elevated SMRs for those with BLs>40 µg/dL; for bladder, lung and larynx cancer; and for COPD. In a small subsample of the US cohort (n=115) who were interviewed, we found no association between smoking and BL.
We found strong positive mortality trends, with increasing BL level, for several outcomes in internal analysis. Many of these outcomes are associated with smoking, for which we had no data. A borderline trend was found for brain cancer, not associated with smoking.
通过一项大型死亡率研究，进一步调查无机铅在成年人中是否为致癌物，或是否与血压升高及肾损伤有关。
我们通过Cox回归对三个有血铅（BL）数据的铅暴露工人队列（美国、芬兰、英国）的死亡率进行了内部分析，包括超过88000名工人和超过14000例死亡。我们的暴露指标是最高血铅值。我们还使用特定国家的背景率进行了外部分析。
合并队列的血铅中位数为26μg/dL，1990年的首次血铅检测均值，且96%为男性。50%的人进行了不止一次血铅检测（平均7次）。使用每个工人的最高血铅值的对数，发现肺癌、慢性阻塞性肺疾病（COPD）、中风和心脏病有显著（p<0.05）的正相关趋势，而膀胱癌、脑癌和喉癌有临界显著趋势（0.05≤p≤0.10）。所有三个队列的大多数结果是一致的。在外部比较中，我们发现血铅>40μg/dL的人群中，膀胱癌、肺癌和喉癌以及COPD的标准化死亡比（SMR）显著升高。在美国队列的一个小亚组（n=115）中进行访谈时，我们发现吸烟与血铅之间没有关联。
我们在内部分析中发现，随着血铅水平升高，几种结局有很强的正相关死亡趋势。其中许多结局与吸烟有关，而我们没有相关数据。脑癌有一个临界趋势，与吸烟无关。
