Examining the Relationship between Trace Lithium in Drinking Water and the Rising Rates of Age-Adjusted Alzheimer’s Disease Mortality in Texas

Article type: Research Article

Authors: Fajardo, Val Andrew^{a; c; *} | Fajardo, Val Andrei^b | LeBlanc, Paul J.^{a; c} | MacPherson, Rebecca E.K.^{a; d; *}

Affiliations: [a] Department of Health Sciences, Brock University, St. Catharines, ON, Canada | [b] Department of Actuarial Sciences, University of Waterloo, Waterloo, ON, Canada | [c] Centre for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada | [d] Centre for Neuroscience, Brock University, St. Catharines, ON, Canada

Correspondence: [*] Correspondence to: Dr. Val Andrew Fajardo, PhD, NSERC Postdoctoral Fellow and Dr. Rebecca E.K. MacPherson, PhD, Assistant Professor, Department of Health Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada. E-mail: rmacpherson@brocku.ca (V. A. Fajardo) and rmacpherson@brocku.ca (R. E. K. MacPherson).

Abstract: Background:Alzheimer’s disease (AD) mortality rates have steadily increased over time. Lithium, the current gold standard treatment for bipolar disorder, can exert neuroprotective effects against AD. Objective:We examined the relationship between trace levels of lithium in drinking water and changes in AD mortality across several Texas counties. Methods:6,180 water samples from public wells since 2007 were obtained and averaged for 234 of 254 Texas counties. Changes in AD mortality rates were calculated by subtracting aggregated age-adjusted mortality rates obtained between 2000–2006 from those obtained between 2009–2015. Using aggregated rates maximized the number of counties with reliable mortality data. Correlational analyses between average lithium concentrations and changes in AD mortality were performed while also adjusting for gender, race, education, rural living, air pollution, physical inactivity, obesity, and type 2 diabetes. Results:Age-adjusted AD mortality rate was significantly increased over time (+27%, p < 0.001). Changes in AD mortality were negatively correlated with trace lithium levels (p = 0.01, r = –0.20), and statistical significance was maintained after controlling for most risk factors except for physical inactivity, obesity, and type 2 diabetes. Furthermore, the prevalence of obesity and type 2 diabetes positively correlated with changes in AD mortality (p = 0.01 and 0.03, respectively), but also negatively correlated with trace lithium in drinking water (p = 0.05 and <0.0001, respectively). Conclusion:Trace lithium in water is negatively linked with changes in AD mortality, as well as obesity and type 2 diabetes, which are important risk factors for AD.

Keywords: Dementia, GSK3, neuroprotection, obesity, type 2 diabetes

DOI: 10.3233/JAD-170744

Journal: Journal of Alzheimer's Disease, vol. 61, no. 1, pp. 425-434, 2018