Lithium in drinking water and Alzheimer's dementia: Epidemiological Findings from National Data Base of Japan

The aim of this study was to investigate the association between lithium levels in drinking water and prevalence of Alzheimer's dementia (AD).

Lithium levels in the drinking water of 808 cities and wards (i.e., 785 Japanese cities of 46 prefectures and 23 wards of Tokyo) in Japan were examined in relation to the prevalence of AD during the 5 years from 2010 to 2014, which was calculated on the basis of the national data base of Ministry of Health, Labor, and Welfare of Japan. Multiple regression analyses were used to investigate the association of lithium levels with the prevalence of AD with adjustment for relevant factors (proportions of one-person households as a family factor and people in primary industry employment as a job factor, annual total sunshine hours as a meteorological factor, and total number of beds of psychiatric hospitals as a medical factor) in total, male, and female elderly populations.

The adjusted model showed a significant inverse association of lithium levels with female, but not with male, or total prevalence of AD.

These findings suggest that higher lithium levels in drinking water may be associated with lower prevalence of AD in female, but not male, populations.