Baastrup Rikke, Sørensen Mette, Balstrøm Thomas, Frederiksen Kirsten, Larsen Carsten Langtofte, Tjønneland Anne, Overvad Kim, Raaschou-Nielsen Ole
Danish Cancer Society, Institute of Cancer Epidemiology, Strandboulevarden 49, Copenhagen, Denmark.
Environ Health Perspect. 2008 Feb;116(2):231-7. doi: 10.1289/ehp.10623.
Arsenic is a well-known carcinogen, which is often found in drinking-water. Epidemiologic studies have shown increased cancer risks among individuals exposed to high concentrations of arsenic in drinking-water, whereas studies of the carcinogenic effect of low doses have had inconsistent results.
Our aim was to determine if exposure to low levels of arsenic in drinking-water in Denmark is associated with an increased risk for cancer.
The study was based on a prospective Danish cohort of 57,053 persons in the Copenhagen and Aarhus areas. Cancer cases were identified in the Danish Cancer Registry, and the Danish civil registration system was used to trace and geocode residential addresses of the cohort members. We used a geographic information system to link addresses with water supply areas, then estimated individual exposure to arsenic using residential addresses back to 1970. Average exposure for the cohort ranged between 0.05 and 25.3 microg/L (mean = 1.2 microg/L). Cox's regression models were used to analyze possible relationships between arsenic and cancer.
We found no significant association between exposure to arsenic and risk for cancers of the lung, bladder, liver, kidney, prostate, or colorectum, or melanoma skin cancer; however, the risk for non-melanoma skin cancer decreased with increasing exposure (incidence rate ratio = 0.88/microg/L average exposure; 95% confidence interval, 0.84-0.94). Results adjusted for enrollment area showed no association with non-melanoma skin cancer.
The results indicate that exposure to low doses of arsenic might be associated with a reduced risk for skin cancer.
砷是一种广为人知的致癌物，常见于饮用水中。流行病学研究表明，饮用水中砷浓度高的个体患癌风险增加，而关于低剂量砷致癌作用的研究结果并不一致。
我们的目的是确定丹麦饮用水中低水平砷暴露是否与患癌风险增加有关。
该研究基于丹麦哥本哈根和奥胡斯地区57,053人的前瞻性队列。癌症病例在丹麦癌症登记处确定，丹麦民事登记系统用于追踪队列成员的居住地址并进行地理编码。我们使用地理信息系统将地址与供水区域联系起来，然后利用可追溯至1970年的居住地址估计个体砷暴露量。该队列的平均暴露量在0.05至25.3微克/升之间（均值 = 1.2微克/升）。采用Cox回归模型分析砷与癌症之间的可能关系。
我们发现砷暴露与肺癌、膀胱癌、肝癌、肾癌、前列腺癌、结直肠癌或黑色素瘤皮肤癌的风险之间无显著关联；然而，非黑色素瘤皮肤癌的风险随暴露量增加而降低（发病率比 = 0.88/微克/升平均暴露量；95%置信区间，0.8~0.94）。对入组地区进行校正后的结果显示与非黑色素瘤皮肤癌无关联。
结果表明，低剂量砷暴露可能与皮肤癌风险降低有关。
