Maternal Methylmercury Exposure Through Rice Ingestion and Offspring Development

描述（由申请人提供）：汞是一种全球性污染物和强效神经毒素。甲基汞是毒性最强的汞形式之一，因为它能够穿过血脑屏障和胎盘屏障。食用鱼类被认为是接触甲基汞的主要途径，因为这种形式的汞在水生食物网中是有效的生物迁移剂，而在金枪鱼和鲨鱼等食肉鱼类中，来自海鲜的汞剂量超过95%的甲基汞。日本和伊拉克历史上的甲基汞中毒事件证实，甲基汞暴露对人类健康的影响在发育中的胎儿中最为严重，因为会造成不可逆转的神经损伤。目前的模式，关于母亲在怀孕期间摄入鱼类，支持食用高ω-3脂肪酸但低甲基汞的鱼类，以获得鱼类摄入的益处（即，促进产前神经发育），同时尽量减少胎儿接触甲基汞。然而，在缺乏（或较低水平）omega-3脂肪酸的情况下，母体接触低水平甲基汞对发育中的胎儿的影响方面，仍然存在着重大的知识空白。本研究的主要目的是解决这一知识差距。 在中国西南部贵州省万山镇，600年来的汞开采遗留下来的汞污染严重污染了空气、土壤和水。在该区域，据报告，大米摄入是甲基汞接触的主要途径，而不是鱼类。拟议的研究包括在中国万山招募一个母亲-后代队列，以调查以大米为主食且汞污染升高的人群中后代的神经发育。以往所有关于母体甲基汞暴露和后代健康的研究都包括以鱼类摄入为主要暴露途径的人群。这项研究将在缺乏与鱼类摄入相关的有益微量营养素的情况下，研究甲基汞的暴露情况。 具体目的是首次确定产前是否存在关系， 在以大米为母体甲基汞暴露主要途径的人群中，甲基汞暴露和后代神经发育之间的关系，同时考虑了其他已知的令人关切的混杂因素，包括母体营养状况和其他间接措施。这项研究的结果将使卫生专业人员能够制定更多的保护性指南，以减少由于产前甲基汞暴露对后代造成的不可逆的神经发育损害。此外，大米是世界一半以上人口的主食;因此， 关键是要调查通过产妇接触甲基汞的潜在健康风险， 摄入大米对发育中的胎儿的影响最大，因为胎儿是最容易受到甲基汞有害影响的人群。

DESCRIPTION (provided by applicant): Mercury is a global pollutant and potent neurotoxin. Methylmercury is one of the most toxic forms of mercury due to its ability to cross the blood brain and placental barriers. Fish consumption is considered the primary exposure methylmercury pathway because this form of mercury is efficiently biomagnified in the aquatic food web and the mercury dose from seafood is greater than 95% methylmercury in predatory fish, like tuna and shark. Historical methylmercury poisonings in Japan and Iraq confirmed human health impacts from methylmercury exposure were most severe in the developing fetus due to irreversible neural damage. The current paradigm, with respect to maternal ingestion of fish during gestation, supports consumption of fish high in omega-3 fatty acids but low in methylmercury to gain the benefits of fish ingestion (i.e., promote prenatal neurodevelopment), while minimizing exposure of the fetus to methylmercury. However, there remains a critical knowledge gap concerning the effect of low-level maternal methylmercury exposure on the developing fetus in the absence of (or lower level of) omega-3 fatty acids. The primary aim of this study is to address this knowledge gap. In the town of Wanshan, Guizhou province, southwestern China, a legacy of mercury contamination from 600 years of mercury mining has severely polluted the air, soil and water. In this region, rice ingestion was reported as the primary methylmercury exposure pathway, not fish. The proposed study includes recruitment of a mother-offspring cohort in Wanshan, China, to investigate offspring neurodevelopment among a population where rice is a staple food and mercury contamination is elevated. All previous studies concerning maternal methylmercury exposure and offspring health included populations where fish ingestion was the primary exposure pathway. This study will examine methylmercury exposure in the absence of the same beneficial micronutrients associated with fish ingestion. The specific aim is to establish for the first time, whether a relationship exists between prenatal methylmercury exposure and offspring neurodevelopment in a population where rice is the primary maternal methylmercury exposure pathway, while accounting for other known confounders of concern, including maternal nutritional status and other indirect measures. Results from this study will enable health professionals to develop more protective guidelines to reduce irreversible neurodevelopmental damage to offspring due to prenatal methylmercury exposure. Additionally, rice is a staple food for more than half the world's population; therefore, it is critical to investigate the potential health risks of methylmercury exposure through maternal ingestion of rice to the developing fetus, the most susceptible population to the deleterious effects of methylmercury.