More than two billion people worldwide have suffered thyroid disorders from either iodine deficiency or excess. By creating the national map of groundwater iodine throughout China, we reveal the spatial responses of diverse health risks to iodine in continental groundwater. Greater non-carcinogenic risks relevant to lower iodine more likely occur in the areas of higher altitude, while those associated with high groundwater iodine are concentrated in the areas suffered from transgressions enhanced by land over-use and intensive anthropogenic overexploitation. The potential roles of groundwater iodine species are also explored: iodide might be associated with subclinical hypothyroidism particularly in higher iodine regions, whereas iodate impacts on thyroid risks in presence of universal salt iodization exhibit high uncertainties in lower iodine regions. This implies that accurate iodine supply depending on spatial heterogeneity and dietary iodine structure optimization are highly needed to mitigate thyroid risks in iodine-deficient and -excess areas globally.

全世界有超过 20 亿人因碘缺乏或碘过量而患上甲状腺疾病。通过创建全国地下水碘地图，我们揭示了大陆地下水中碘对不同健康风险的空间响应。与低碘相关的更大非致癌风险更有可能发生在海拔较高的地区，而与高地下水碘相关的风险则集中在因土地过度使用和密集的人为过度开发而加剧的海侵地区。还探讨了地下水碘种类的潜在作用：碘化物可能与亚临床甲状腺功能减退症有关，特别是在高碘地区，而在普遍食盐碘化的情况下，碘酸盐对甲状腺风险的影响在低碘地区表现出高度不确定性。这意味着非常需要基于空间异质性和膳食碘结构优化的准确碘供应，以减轻全球碘缺乏和碘过剩地区的甲状腺风险。