UCSF Study Links Lithium in Tap Water to Wolff-Parkinson-White Syndrome in Children

An ecological study led by researchers at the University of California, San Francisco (UCSF) evaluated whether environmental exposure to naturally occurring lithium via public drinking water correlates with the occurrence of pediatric heart conduction defects. According to findings published in the Journal of Clinical Investigation, children residing in areas with higher concentrations of lithium in municipal tap water exhibited an increased likelihood of being diagnosed with Wolff-Parkinson-White (WPW) syndrome jci.orgJournal of Clinical Investigationjci.orgOpen source ↗. WPW syndrome involves an congenital atrioventricular accessory pathway that can trigger supraventricular tachycardia (SVT) and, in rare instances, fatal arrhythmias.

California Cohort Analysis

The primary research analyzed health and water-monitoring records for 2,329,090 California patients under 18 years of age (mean age 8.2 ± 5.9 years, 47.8% female) using multivariable logistic regression. Within this cohort, 686 individuals (0.03%) had a documented diagnosis of WPW. Statistical analysis revealed that living in counties where lithium concentrations were at or above the 75th percentile was associated with a 71% increase in the odds of a WPW diagnosis (odds ratio 1.71, 95% CI 1.44 to 2.03) compared to lower areas. Residing in regions exceeding the established health-based screening limit corresponded to a 29% greater odds of diagnosis (OR 1.29, 95% CI 1.05 to 1.58).

Secondary Validation and Clinical Endpoints

The authors replicated their methodology in an independent statewide cohort of nearly 2 million pediatric patients in New York, where water lithium concentrations above 10 parts per billion similarly correlated with elevated odds of a WPW diagnosis. Validation models confirmed that areas in the top 25th percentile for lithium also exhibited a statistically significant rise in related clinical events, including SVT, syncope, palpitations, and catheter ablation interventions.

The authors emphasized that the ecological methodology evaluates population-level data based on residence rather than measured individual consumption or serum levels. While maternal pharmacological lithium therapy has previously been associated with Ebstein's anomaly, these environmental observations establish a statistical association rather than a direct toxicological causal link jci.orgJournal of Clinical Investigationjci.orgOpen source ↗. Further prospective studies are required to determine whether direct prenatal exposure directly affects cardiac electrophysiological development.