硝酸盐摄入与甲状腺癌和甲状腺疾病的风险。
Nitrate intake and the risk of thyroid cancer and thyroid disease.
机构信息
Division of Cancer Epidemiology and Genetics, Department of Health and Human Services, National Cancer Institute, National Institutes of Health, Rockville, MD, USA.
出版信息
Epidemiology. 2010 May;21(3):389-95. doi: 10.1097/EDE.0b013e3181d6201d.
BACKGROUND
Nitrate is a contaminant of drinking water in agricultural areas and is found at high levels in some vegetables. Nitrate competes with uptake of iodide by the thyroid, thus potentially affecting thyroid function.
METHODS
We investigated the association of nitrate intake from public water supplies and diet with the risk of thyroid cancer and self-reported hypothyroidism and hyperthyroidism in a cohort of 21,977 older women in Iowa who were enrolled in 1986 and who had used the same water supply for >10 years. We estimated nitrate ingestion from drinking water using a public database of nitrate measurements (1955-1988). Dietary nitrate intake was estimated using a food frequency questionnaire and levels from the published literature. Cancer incidence was determined through 2004.
RESULTS
We found an increased risk of thyroid cancer with higher average nitrate levels in public water supplies and with longer consumption of water exceeding 5 mg/L nitrate-N (for >or=5 years at >5 mg/L, relative risk [RR] = 2.6 [95% confidence interval (CI) = 1.1-6.2]). We observed no association with prevalence of hypothyroidism or hyperthyroidism. Increasing intake of dietary nitrate was associated with an increased risk of thyroid cancer (highest vs. lowest quartile, RR = 2.9 [1.0-8.1]; P for trend = 0.046) and with the prevalence of hypothyroidism (odds ratio = 1.2 [95% CI = 1.1-1.4]), but not hyperthyroidism.
CONCLUSIONS
Nitrate may play a role in the etiology of thyroid cancer and warrants further study.
背景
硝酸盐是农业地区饮用水的污染物，在一些蔬菜中含量很高。硝酸盐会与甲状腺摄取碘竞争，从而潜在地影响甲状腺功能。
方法
我们调查了从公共供水和饮食中摄入硝酸盐与甲状腺癌风险以及在爱荷华州的 21977 名年龄较大的女性队列中报告的自身甲状腺功能减退症和甲状腺功能亢进症之间的关联，这些女性于 1986 年入组，并且使用相同的供水> 10 年。我们使用硝酸盐测量的公共数据库（1955-1988 年）来估算饮用水中的硝酸盐摄取量。使用食物频率问卷和已发表文献中的水平来估算饮食中硝酸盐的摄入量。通过 2004 年确定癌症发病率。
结果
我们发现公共供水中硝酸盐水平较高与甲状腺癌风险增加有关，并且与消耗超过 5mg/L 硝酸盐-N 的水时间较长有关（> 5mg/L 时> 5 年，相对风险[RR] = 2.6 [95%置信区间（CI）= 1.1-6.2]）。我们未发现与甲状腺功能减退症或甲状腺功能亢进症的患病率有关。饮食中硝酸盐摄入量的增加与甲状腺癌风险增加相关（最高与最低四分位数相比，RR = 2.9 [1.0-8.1]；P 趋势= 0.046），与甲状腺功能减退症的患病率相关（比值比= 1.2 [95% CI = 1.1-1.4]），但与甲状腺功能亢进症无关。
结论
硝酸盐可能在甲状腺癌的病因学中起作用，值得进一步研究。
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