Acidic Drinking Water and Risk of Childhood-Onset Type 1 Diabetes

Abstract

OBJECTIVE—To estimate the associations of acidity and concentration of selected minerals in household tap water with the risk of type 1 diabetes. RESEARCH DESIGN AND METHODS—We designed a population-based case-control study with 64 cases of type 1 diabetes and 250 randomly selected control subjects. Acidity, color, and mineral content were measured in tap water from each participant’s household. RESULTS—Tap water pH 6.2–6.9 was associated with a fourfold higher risk of type 1 diabetes compared with pH ≥7.7 (OR 3.73, 95% CI 1.52–9.15). This result was similar after exclusion of individuals with the highly protective HLA-DQB1*0602 allele, but adjustment for maternal education, urban/rural residence, sex, and age tended to strengthen the estimated association. Higher tap water concentration of zinc was associated with lower risk of type 1 diabetes after adjustment for pH and other possible confounders, but the overall association was strictly not significant. CONCLUSIONS—These results suggest the possibility that quality of drinking water influences the risk of type 1 diabetes. The possible mechanisms by which water acidity or mineral content may be involved in the etiology of type 1 diabetes remain unknown, but the mechanisms are most likely indirect and may involve an influence on survival of microorganisms in the water.