Groundwater Lithium Availability Association with Physical and Mental Health Outcomes in United States Populations

Abstract Natural consumption of lithium has been linked to a range of beneficial physical and mental health outcomes. We examined the association of regional groundwater lithium concentrations with 12 such outcomes across 47 continental US states and Washington DC in two nationally representative samples from the Behavioral Risk Factor Surveillance System (BRFSS). As drinking groundwater is more likely in rural counties, we performed separate logistic regression analyses in rural and urban populations. Associations between groundwater lithium concentrations and health outcomes were stronger in rural residents and robust to demographics in both rural and urban samples. Compared to regions with lithium concentrations less than 10 µg/L, residents of rural counties with lithium concentrations of 30 µg/L or more exhibited consistently reduced odds of depression diagnosis (adjusted odds ratios [ORs] ranged from 0.64 to 0.88), functional impairment (adjusted ORs ranged from 0.33 to 0.87), and kidney disease diagnosis (adjusted ORs ranged from 0.49 to 0.93); whereas reduced odds of cancer diagnosis were less consistent (adjusted ORs ranged from 0.53 to 1.07). Effect sizes were largest in regions with the highest lithium concentrations. Results in rural populations show a positive correlation ( r s (90) = .79, P < .001) between higher lithium availability and improved health outcomes. More research is needed to determine if optimizing lithium intake may improve physical and mental health.