BACKGROUND: Perfluorinated alkyl substances (PFAS) are suggested to impair immune function in children. Previous studies investigating associations between prenatal PFAS exposure and common infections were performed in background-exposed populations whilst studies from high-exposed populations are lacking. OBJECTIVES: To investigate the association between prenatal PFAS exposure from contaminated drinking water and common infections in children aged 6 months to 7 years in Ronneby, Sweden. METHODS: The cohort included 17,051 children, born 2003-2013, to mothers residing in Blekinge County at least one year within the five years before childbirth. Primary care diagnoses of infections in eyes, ears, respiratory- and urinary tract were retrieved from the Blekinge Healthcare Register. The residential history of the mothers served as a proxy for prenatal exposure
very high, high, intermediate, and background. We estimated hazard ratios (HR) by Cox proportional hazards regression with the Andersen and Gill extension for recurring events. RESULTS: We observed an increased risk for ear infections (HR 1.28
95% CI 1.03-1.58) in children with very high prenatal PFAS exposure, as well as suggestive but non-significant associations with eye- and urinary tract infections. Children with intermediate prenatal exposure had a reduced risk of eye infections (HR 0.86
95% CI 0.77-0.95). No increased risk of respiratory tract infections was observed in any of the exposure categories. DISCUSSION: This study was the first to investigate the association between high prenatal PFAS levels and common infections diagnosed in primary care, and it adds to a growing body of evidence of the potential immunotoxicity of early-life PFAS exposure.