Yang Chun-Yuh, Chang Chih-Ching, Ho Shu-Chen, Chiu Hui-Fen
Faculty of Public Health, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan 80708.
J Toxicol Environ Health A. 2008;71(8):533-8. doi: 10.1080/15287390801907509.
Arsenic has been well documented as the major risk factor for blackfoot disease (BFD), a unique peripheral vascular disease that was endemic to the southwestern coast of Taiwan, where residents consumed high-arsenic artesian well water for more than 50 yr. Chronic arsenic exposure was also reported to be associated with increased mortality attributed to colon cancer. A tap-water supply system was implemented in the early 1960s in the BFD-endemic areas. Artesian well water was no longer used for drinking and cooking after the mid-1970s. The objective of this study was to determine whether colon cancer mortality decreased after the improvement of the drinking-water supply system through elimination of arsenic ingestion from artesian well water. Standardized mortality ratios (SMRs) for colon cancer were calculated for the BFD-endemic area for the years 1971-2006. Results showed that mortality due to colon cancer declined in males, but not in females, gradually after the improvement of drinking-water supply system. Based on the reversibility criterion, the association between arsenic exposure and colon cancer incidence is likely to be causal for males but not females. The possibility that our results may be due to chance should be considered; however, gender-specific differences in arsenic metabolism may be a critical factor.
砷已被充分证明是黑脚病（BFD）的主要风险因素，黑脚病是一种独特的周围血管疾病，曾在台湾西南海岸流行，当地居民饮用高砷自流井水长达50多年。据报道，长期接触砷还与结肠癌导致的死亡率增加有关。20世纪60年代初，在黑脚病流行地区实施了自来水供应系统。20世纪70年代中期以后，自流井水不再用于饮用和烹饪。本研究的目的是确定通过消除自流井水中砷的摄入来改善饮用水供应系统后，结肠癌死亡率是否下降。计算了1971 - 2006年黑脚病流行地区结肠癌的标准化死亡率（SMR）。结果表明，饮用水供应系统改善后，男性结肠癌死亡率逐渐下降，但女性没有下降。根据可逆性标准，砷暴露与结肠癌发病率之间的关联对男性可能是因果关系，但对女性不是。应考虑我们的结果可能是偶然的可能性；然而，砷代谢的性别差异可能是一个关键因素。
