Steenland K, Boffetta P
National Institute for Occupational Safety and Health, Cincinnati, Ohio 45226, USA.
Am J Ind Med. 2000 Sep;38(3):295-9. doi: 10.1002/1097-0274(200009)38:3<295::aid-ajim8>3.0.co;2-l.
Lead is only weakly mutagenic, but in vitro it inhibits DNA repair and acts synergistically with other mutagens. Lead acetate administered orally, cutaneously, or intraperitoneally causes kidney cancer, brain cancer (gliomas), and lung cancer in rodents, and acts synergistically with other carcinogens. Most cytogenetic studies of exposed workers have shown increases in chromosome aberrations or sister chromatid exchange, including some studies with positive-exposure response trends. There are eight studies of cancer mortality or incidence among highly exposed workers; most are cohort studies of lead smelter or battery workers exposed decades ago.
We reviewed the epidemologic studies with regard to cancer.
These studies provide some evidence of increased risk of lung cancer (RR = 1.30, 1.15-1.46, 675 observed deaths) and stomach cancer (combined RR = 1.34, 1.14-1.57, 181 observed). However, the lung cancer findings are not consistent across studies, and confounding by arsenic may affect the study with the highest lung cancer RR. Exclusion of that study yields a combined lung cancer RR of 1.14 (1.04-1.73). There is little evidence of increased risk of kidney cancer (combined RR = 1.01, 0. 72-1.42, 40 observed) or brain cancer (combined RR = 1.06, 0.81-1.40, 69 observed). However, two studies show a two-fold increase in kidney cancer, and one study shows a significant excess of gliomas. IARC classified lead as a "possible human carcinogen" based on sufficient animal data and insufficient human data in 1987. Six of the eight studies cited above have been published since 1987.
Overall, there is only weak evidence associating lead with cancer; the most likely candidates are lung cancer, stomach cancer, and gliomas.
铅的致突变性较弱，但在体外它会抑制DNA修复，并与其他诱变剂产生协同作用。经口、经皮或腹腔注射醋酸铅可在啮齿动物中引发肾癌、脑癌（神经胶质瘤）和肺癌，并与其他致癌物产生协同作用。大多数针对接触铅的工人的细胞遗传学研究显示染色体畸变或姐妹染色单体交换增加，包括一些呈现出暴露-反应阳性趋势的研究。有八项关于高暴露工人癌症死亡率或发病率的研究；大多数是对几十年前接触铅的冶炼厂工人或电池厂工人的队列研究。
我们回顾了有关癌症的流行病学研究。
这些研究提供了一些证据，表明肺癌风险增加（相对危险度=1.30，95%可信区间为1.15 - 1.46，观察到675例死亡）以及胃癌风险增加（合并相对危险度=1.34，95%可信区间为1.14 - 1.57，观察到181例）。然而，各项研究中关于肺癌的结果并不一致，并且砷的混杂作用可能会影响相对危险度最高的肺癌研究。排除该研究后，合并的肺癌相对危险度为1.14（95%可信区间为1.04 - 1.73）。几乎没有证据表明肾癌（合并相对危险度=1.01，95%可信区间为0.72 - 1.42，观察到40例）或脑癌（合并相对危险度=1.06，95%可信区间为0.81 - 1.40，观察到69例）风险增加。然而，有两项研究显示肾癌风险增加了两倍，还有一项研究显示神经胶质瘤显著增多。1987年，国际癌症研究机构（IARC）基于充分的动物数据和不充分的人类数据将铅归类为“可能的人类致癌物”。上述八项研究中有六项是自一九八七年以来发表的。
总体而言，仅有微弱证据表明铅与癌症有关；最有可能相关的是肺癌、胃癌和神经胶质瘤。
