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

Background: 

There are indications that early-life exposure to perfluoroalkyl substances (PFAS) can impact neurodevelopment, but results are inconclusive. The objective was to investigate if high early-life exposure to primarily perfluorohexanesulfonic acid (PFHxS) and perfluorooctanesulfonic acid (PFOS) increases the risk of developmental language disorder in children up to seven years of age.
Methods: 

A register-based cohort of all children born 1998–2013 in Blekinge county, Sweden, was studied. Maternal residential history, that is, with or without highly PFAS-contaminated drinking water, during the 5-year period before childbirth was used as a proxy for early-life exposure. Exposure was categorized as high (n = 646), intermediate (n = 1,650), or background (n = 9,599). We used Cox proportional hazards regression to estimate hazard ratios (HR) for (1) referral to a speech- and language pathologist after routine screening at Child Health Services, and (2) subsequent language disorder diagnosis after clinical assessment. Models were adjusted for parity, maternal age, education level, and smoking, and explored effect modification by sex.
Results: 

In children from the high-exposed area, the adjusted HR for referral was 1.23 (95% CI = 1.03, 1.47) and 1.13 (95% CI = 0.97, 1.56) for subsequent diagnosis. There was no increased risk in the intermediate exposure category.
Conclusion: 

Children, particularly girls, with high exposure had an increased risk of both referral and confirmed developmental language disorder. Further research is needed on PFAS in the context of general neurodevelopment, for which language development is a proxy.