Overlooked Fluorine Deficiency in Children of South and East China May Be Exacerbated by Climate Change: Evidence from the National Assessment

Fluoride (F) exhibits toxicity in excess but provides health benefits in moderate concentrations. While extensive research has focused on elevated F levels in groundwater, studies are scarce on F concentrations in surface water, a crucial drinking water source. In this study, we compiled a comprehensive database encompassing three decades of oral epidemiological data from over 140,000 Chinese children (6–17 years) and F concentrations in 160 freshwater lakes and reservoirs across China to investigate the health risks, environmental drivers, and future evolution of F in surface water. We found that insufficient F intake through surface water does not cause dental fluorosis but rather dental caries in children. East and South China regions bear the highest health burdens, quantified in Disability-adjusted life years (DALYs), reflecting the extensive use of surface water for drinking purposes. Multiple linear regression analysis indicated that soil & geology largely control F concentrations, with precipitation exerting a significant negative effect, accounting for 16.5% of the explained variance. As China anticipates increased precipitation in the future, a potentially elevated risk of fluorine deficiency in South and East China demands vigilant attention.