Arbuckle T E, Sherman G J, Corey P N, Walters D, Lo B
Department of Preventive Medicine and Biostatistics, University of Toronto, Canada.
Arch Environ Health. 1988 Mar-Apr;43(2):162-7. doi: 10.1080/00039896.1988.9935846.
The relation between maternal exposure to nitrates in drinking water and risk of delivering an infant with a central nervous system (CNS) malformation was examined by means of a case-control study in New Brunswick, Canada. All cases of CNS defects for a "high" and a "low" prevalence area of New Brunswick, for the years 1973-1983, were included in the study. Controls were selected randomly from the livebirth files for the province, matched on county of maternal residence and date of birth. One hundred and thirty (130) cases were identified and individually matched with two controls each. Individual water samples were collected from the case and control mother's address given on the birth or stillbirth records. The study revealed that the effect of nitrate exposure in water was modified by whether the source of the drinking water was a private well or a public municipal distribution system. Compared to a baseline nitrate level of 0.1 ppm, exposure to nitrate levels of 26 ppm from private well water sources was associated with a moderate, but not statistically significant, increase in risk (risk odds ratio = 2.30; 95% confidence interval = 0.73-7.29). If the source of drinking water was a municipal distribution system or a private spring, an increase in nitrate exposure was associated with a decrease in risk of delivering a CNS-malformed infant; however, these effect estimates were not statistically significant. The positive increase in risk with nitrate exposure from well water sources requires further study using a larger case series and a larger proportion of exposures to nitrate levels exceeding 5 ppm.
通过加拿大新不伦瑞克省的一项病例对照研究，调查了孕妇饮用水中硝酸盐暴露与分娩中枢神经系统（CNS）畸形婴儿风险之间的关系。1973年至1983年期间，新不伦瑞克省“高”和“低”患病率地区的所有CNS缺陷病例都纳入了该研究。对照组从该省的活产记录中随机选取，根据产妇居住县和出生日期进行匹配。共确定了130例病例，每个病例分别与两名对照进行匹配。从出生或死产记录上的病例和对照母亲的住址采集个体水样。研究表明，饮用水中硝酸盐暴露的影响因饮用水来源是私人水井还是公共市政供水系统而有所不同。与0.1 ppm的基线硝酸盐水平相比，来自私人井水水源的26 ppm硝酸盐暴露与风险适度增加相关，但无统计学意义（风险比=2.30；95%置信区间=0.73 - 7.29）。如果饮用水来源是市政供水系统或私人泉水，硝酸盐暴露增加与分娩CNS畸形婴儿的风险降低相关；然而，这些效应估计无统计学意义。井水水源硝酸盐暴露导致的风险正向增加需要使用更大的病例系列以及更大比例的硝酸盐暴露水平超过5 ppm的情况进行进一步研究。
