Picetti Roberto, Deeney Megan, Pastorino Silvia, Miller Mark R, Shah Anoop, Leon David A, Dangour Alan D, Green Rosemary
Centre on Climate Change and Planetary Health, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
Centre on Climate Change and Planetary Health, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
Environ Res. 2022 Jul;210:112988. doi: 10.1016/j.envres.2022.112988. Epub 2022 Feb 22.
Pollution of water sources, largely from wide-scale agricultural fertilizer use has resulted in nitrate and nitrite contamination of drinking water. The effects on human health of raised nitrate and nitrite levels in drinking water are currently unclear.
We conducted a systematic review of peer-reviewed literature on the association of nitrate and nitrite in drinking water with human health with a specific focus on cancer.
We searched eight databases from 1 January 1990 until 28 February 2021. Meta-analyses were conducted when studies had the same exposure metric and outcome.
Of 9835 studies identified in the literature search, we found 111 studies reporting health outcomes, 60 of which reported cancer outcomes (38 case-control studies; 12 cohort studies; 10 other study designs). Most studies were set in the USA (24), Europe (20) and Taiwan (14), with only 3 studies from low and middle-income countries. Nitrate exposure in water (59 studies) was more commonly investigated than nitrite exposure (4 studies). Colorectal (15 studies) and gastric (13 studies) cancers were the most reported. In meta-analyses (4 studies) we identified a positive association of nitrate exposure with gastric cancer, OR = 1.91 (95%CI = 1.09-3.33) per 10 mg/L increment in nitrate ion. We found no association of nitrate exposure with colorectal cancer (10 studies; OR = 1.02 [95%CI = 0.96-1.08]) or cancers at any other site.
We identified an association of nitrate in drinking water with gastric cancer but with no other cancer site. There is currently a paucity of robust studies from settings with high levels nitrate pollution in drinking water. Research into this area will be valuable to ascertain the true health burden of nitrate contamination of water and the need for public policies to protect human health.
水源污染主要源于大规模使用农业化肥，已导致饮用水中硝酸盐和亚硝酸盐污染。目前尚不清楚饮用水中硝酸盐和亚硝酸盐水平升高对人体健康的影响。
我们对同行评审的关于饮用水中硝酸盐和亚硝酸盐与人类健康关联的文献进行了系统综述，特别关注癌症。
我们检索了1990年1月1日至2021年2月28日的八个数据库。当研究具有相同的暴露指标和结局时，进行荟萃分析。
在文献检索中识别出的9835项研究中，我们发现111项研究报告了健康结局，其中60项报告了癌症结局（38项病例对照研究；12项队列研究；10项其他研究设计）。大多数研究在美国（24项）、欧洲（20项）和台湾地区（14项）开展，只有3项研究来自低收入和中等收入国家。水中硝酸盐暴露（59项研究）比亚硝酸盐暴露（4项研究）更常被调查。报告最多的是结直肠癌（15项研究）和胃癌（13项研究）。在荟萃分析（4项研究）中，我们发现硝酸盐暴露与胃癌呈正相关，每增加10 mg/L硝酸根离子，比值比（OR）=1.91（95%置信区间[CI]=1.09 - 3.33）。我们发现硝酸盐暴露与结直肠癌（10项研究；OR = 1.02 [95%CI = 0.96 - 1.08]）或其他任何部位的癌症均无关联。
我们发现饮用水中的硝酸盐与胃癌有关，但与其他癌症部位无关。目前来自饮用水硝酸盐污染水平高的地区的有力研究较少。对该领域的研究对于确定硝酸盐污染水对健康的真正负担以及制定保护人类健康的公共政策的必要性将具有重要价值。
