Institute of Pharmacology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
J Toxicol Environ Health A. 2012;75(12):684-93. doi: 10.1080/15287394.2012.688486.
The objectives of this study were to (1) examine the relationship between nitrate levels in public water supplies and risk of death from gastric cancer and (2) determine whether calcium (Ca) and magnesium (Mg) levels in drinking water might modify the effects of nitrate on the risk of gastric cancer development. A matched cancer case-control study was used to investigate the relationship between the risk of death attributed to gastric cancer and exposure to nitrate in drinking water in Taiwan. All deaths due to gastric cancer in Taiwan residents from 2006 through 2010 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Deaths from other causes served as controls and were pair-matched to cancer cases by gender, year of birth, and year of death. Information on the levels of nitrate-nitrogen (NO(3)-N), Ca, and Mg in drinking water were collected from Taiwan Water Supply Corporation (TWSC). The municipality of residence for cancer cases and controls was presumed to be the source of the subject's NO(3)-N, Ca, and Mg exposure via drinking water. Relative to individuals whose NO(3)-N exposure levels were <0.38 ppm, the adjusted odds ratio (OR) and 95% confidence interval (CI) for gastric cancer occurrence was 1.16 (1.05-1.29) for individuals who resided in municipalities served by drinking water with a NO(3)-N exposure ≥ 0.38 ppm. There was apparent evidence of an interaction between drinking water NO(3)-N levels and low Ca and Mg intake via drinking water. Our findings showed that the correlation between NO(3)-N exposure and risk of gastric cancer development was influenced by Ca and Mg levels in drinking water. This is the first study to report effects modification by Ca and Mg intake from drinking water on the relationship between NO(3)-N exposure and risk of gastric cancer occurrence. Increased knowledge of the mechanistic interactions between Ca, Mg, and NO(3)-N in reducing risk of gastric cancer development will aid in public policy decisions and setting threshold standards.
(1) 检验公共供水系统中硝酸盐水平与胃癌死亡率之间的关系；(2) 确定饮用水中钙 (Ca) 和镁 (Mg) 水平是否可能改变硝酸盐对胃癌发展风险的影响。本研究采用配对病例对照研究，调查了台湾地区居民饮用水中硝酸盐暴露与胃癌死亡风险之间的关系。从 2006 年至 2010 年，台湾省卫生署生命统计处获得了所有归因于胃癌的台湾居民死亡病例。其他死因的死亡病例作为对照，并按性别、出生年份和死亡年份与癌症病例配对。从台湾自来水公司 (TWSC) 收集了饮用水中硝酸盐氮 (NO3-N)、Ca 和 Mg 的水平信息。癌症病例和对照的居住地被认为是通过饮用水暴露于硝酸盐氮的来源。与暴露于硝酸盐氮水平<0.38ppm 的个体相比，居住在饮用水硝酸盐氮暴露水平≥0.38ppm 的市政供水区域的个体，其发生胃癌的调整后比值比 (OR) 和 95%置信区间 (CI) 为 1.16(1.05-1.29)。饮用水硝酸盐氮水平与低 Ca 和 Mg 摄入之间存在明显的交互作用。我们的研究结果表明，NO3-N 暴露与胃癌发展风险之间的相关性受到饮用水中 Ca 和 Mg 水平的影响。这是第一项报告饮用水中 Ca 和 Mg 摄入对 NO3-N 暴露与胃癌发生风险之间关系的影响修饰作用的研究。更多地了解 Ca、Mg 和 NO3-N 之间在降低胃癌发展风险方面的机制相互作用，将有助于公共政策决策和设定阈值标准。
