Prenatal methylmercury poisoning and neurocognitive impairment in Minamata.

The Minamata disease, which was first identified in 1956, is a severe form of methylmercury food poisoning that affected the city of Minamata in Japan. This disease had a significant impact on the health of the local population, particularly children who were born with severe neurological symptoms, known as congenital Minamata disease (CMD). Despite the severity of the disease, there has been limited research on the health effects of prenatal methylmercury exposure on individuals who were born in the affected areas during the same time period as those with CMD. To address this gap in knowledge, a study was conducted using historical data from a clinical study carried out in 1970 in Minamata City and the nearby Amakusa island region. The study involved a total of 416 junior high school students who were divided into three categories based on their level of exposure to methylmercury: those who lived in highly exposed areas, those who lived in moderately exposed areas, and those who lived in less exposed areas. The researchers found that the prevalence of neurocognitive impairment was significantly higher among students who lived in highly exposed areas compared to those who lived in less exposed areas. Specifically, the prevalence of neurocognitive impairment was 2.08 times higher, and the prevalence of severe neurocognitive impairment was 2.84 times higher, in the highly exposed area compared to the less exposed area. These findings suggest that prenatal methylmercury exposure had a significant impact on the neurocognitive function of individuals who were born in the affected areas, including those with CMD and those who were born at the same time as CMD patients. The study's results highlight the importance of considering the long-term effects of environmental pollution on human health and the need for further research on the health impacts of methylmercury exposure. Link: https://pubmed.ncbi.nlm.nih.gov/40440848/