Environmental Working Group, 1436 U Street NW Suite 100, Washington, DC, 20009, USA.
Environmental Working Group, 1436 U Street NW Suite 100, Washington, DC, 20009, USA.
Environ Res. 2019 Sep;176:108442. doi: 10.1016/j.envres.2019.04.009. Epub 2019 Jun 11.
Nitrate ingestion from drinking water has been associated with an increased risk of adverse birth outcomes as well as elevated risk of colorectal cancer and several other cancers. Yet, to date, no studies have attempted to quantify the health and economic impacts due to nitrate in drinking water in the United States.
This study presents a first-of-its-kind comprehensive assessment of nitrate exposure from drinking water for the entire United States population. This exposure assessment serves as the basis for our analysis of the annual nitrate-attributable disease cases in the United States and the associated economic losses due to medical costs and lost productivity. Additionally, through a meta-analysis of studies on drinking water nitrate and colorectal cancer, we examine the exposure-response relationship for nitrate and cancer risk.
On the basis of national nitrate occurrence data and relative risk ratios reported in the epidemiology literature, we calculated that annually, 2939 cases of very low birth weight, 1725 cases of very preterm birth, and 41 cases of neural tube defects could be related to nitrate exposure from drinking water. For cancer risk, combining nitrate-specific risk estimates for colorectal, ovarian, thyroid, kidney, and bladder cancers results in a range of 2300 to 12,594 annual nitrate-attributable cancer cases (mean: 6537 estimated cases). For medical expenditures alone, this burden of cancer corresponds to an annual economic cost of 250 million to 1.5 billion U.S. dollars, together with a potential 1.3 to 6.5 billion dollar impact due to lost productivity. With the meta-analysis of eight studies of drinking water nitrate and colorectal cancer, we observed a statistically significant positive association for nitrate exposure and colorectal cancer risk and calculated a one-in-one million cancer risk level of 0.14 mg/L nitrate in drinking water.
Health and economic analyses presented here suggest that lowering exposure to nitrate in drinking water could bring economic benefits by alleviating the impacts of nitrate-associated diseases.
饮用水中的硝酸盐摄入与不良出生结局风险增加以及结直肠癌和其他几种癌症风险升高有关。然而，迄今为止，尚无研究试图量化美国饮用水中硝酸盐对健康和经济的影响。
本研究首次对美国全人口饮用水中的硝酸盐暴露进行了全面评估。这种暴露评估是我们分析美国每年因硝酸盐引起的疾病病例以及因医疗费用和生产力损失而导致的经济损失的基础。此外，通过对饮用水硝酸盐和结直肠癌的研究进行荟萃分析，我们研究了硝酸盐与癌症风险的暴露-反应关系。
根据全国硝酸盐发生数据和流行病学文献中报告的相对风险比，我们计算出每年有 2939 例极低出生体重、1725 例早产和 41 例神经管缺陷可能与饮用水中的硝酸盐暴露有关。对于癌症风险，将结直肠癌、卵巢癌、甲状腺癌、肾癌和膀胱癌的特定硝酸盐风险估计值结合起来，可导致每年有 2300 至 12594 例硝酸盐归因癌症病例（平均：估计有 6537 例病例）。仅就医疗支出而言，这种癌症负担相当于每年 2.5 亿至 15 亿美元的经济成本，以及由于生产力损失而可能造成的 13 亿至 65 亿美元的影响。通过对八项关于饮用水硝酸盐和结直肠癌的研究进行荟萃分析，我们观察到硝酸盐暴露与结直肠癌风险之间存在统计学上的显著正相关关系，并计算出饮用水中硝酸盐的百万分之一癌症风险水平为 0.14mg/L。
这里提出的健康和经济分析表明，降低饮用水中硝酸盐的暴露水平可能会通过减轻硝酸盐相关疾病的影响带来经济效益。
