Developmental language disorders in preschool children after high exposure to perfluoroalkyl substances from contaminated drinking water in Ronneby, Sweden

BACKGROUND: There are indications that prenatal exposure to perfluoroalkyl substances (PFAS) might impact neurodevelopment, including language and communication, but results from epidemiological studies are inconclusive and studies from high-exposed populations are sparse. OBJECTIVE AND AIM: To investigate associations between prenatal exposure to primarily PFHxS and PFOS and developmental language disorder in children up to seven years of age. METHODS: Register-based cohort of children, born 1998-2013 in the county of Blekinge, Sweden. Maternal residency in Ronneby municipality, with or without highly PFAS contaminated drinking water during the five-year period before childbirth, was used as a proxy for increased prenatal exposure. We included 646 Ronneby children with high PFAS exposure, 1,650 children with intermediate exposure and 9,599 children from county with background exposure. We used Cox proportional hazards regression to estimate hazard ratios (HR) for 1) referral to speech- and language pathologist (SLP) after screening at Child Health Services and 2) ICD-10 diagnosis from at least two clinical assessments by a SLP. Models were adjusted for parity, maternal age, education level, and smoking. We explored effect modification by sex. RESULTS: The overall adjusted HR for referral to SLP for children with high prenatal exposure was 1.23 (95% CI: 1.03-1.47). Girls had a higher risk than boys. The HR for ICD-10 diagnosis for children with high prenatal exposure was 1.13 (95% CI: 0.97-1.56), and the association was among girls. Children with intermediate PFAS exposure did not differ from background exposed children. CONCLUSIONS: Children, particularly girls, with high prenatal exposure to PFAS had an increased risk of developmental language delay and disorders. Further research is needed on the role of PFAS in the context of general neurodevelopment, for which language development is a proxy. KEYWORD Register-based population study Delayed language development Developmental language disorder Prenatal exposure Perfluorohexane sulfonic acid (PFHxS) Perfluorooctane sulfonic acid (PFOS)