Higher Groundwater Selenium Exposure Is Associated with Better Memory: A Project FRONTIER Study

Background: Exposure to elements in groundwater (toxic or beneficial) is commonplace yet, outside of lead and mercury, little research has examined the impact of many commonly occurring exposures on mental abilities during the aging process. Selenium has antioxidant properties as part of the glutathione peroxidase system and may have protective effects on memory abilities. Objectives: To investigate the relationship of groundwater selenium exposure to neuropsychological status. Method: Analysis of data from 484 participants (148 men and 336 women) of Project FRONTIER, a community-based participatory research study of the epidemiology of health issues of rural-dwelling adults and elders. Results: Estimated selenium exposure (current and long-term) was specifically related to memory functioning without relation to other neurocognitive domains. The significant, positive link between selenium and memory (Immediate and Delayed) scores held regardless of APOE4 status as well as when the sample was restricted to only those without cognitive dysfunction. Current selenium was also associated with significantly reduced risk of cognitive decline prospectively. Conclusions: Higher selenium levels were associated with better memory functioning as well as reduced risk of cognitive decline among this community-based sample. Given the antioxidant properties of selenium, and the well-documented link between oxidative stress and the development of cognitive dysfunction and Alzheimer’s disease, additional research is necessary to determine the utility of groundwater selenium monitoring as a potential population-wide prevention effort against Alzheimer’s disease.