Developmental immunotoxicity of perfluoroalkyl substances (PFASs) in a population of highly-exposed children

Exposures to perfluoroalkyl substances (PFASs), a class of persistent chemicals, have been linked to an array of adverse health outcomes including reduced antibody response to vaccination. The COVID-19 pandemic has focused attention on the serious implications of PFAS immunotoxicity. However, there is a lack of epidemiological studies on clinical immune outcomes (e.g., infections or asthma) in children, whose developing immune system is highly sensitive to chemical exposures. This proposal (PFAS-ITOX) addresses this research gap by leveraging a unique cohort of children with a wide range of PFAS exposures (background to highly exposed) and detailed medical records to investigate the potential immunotoxic effects of prenatal and childhood PFAS exposures on clinically relevant outcomes, including COVID-19 incidence. It was discovered in 2013 that one of two municipal water supplies in Ronneby, Sweden was delivering water that was highly contaminated by PFASs from firefighting foam runoff at a nearby military airport. Earlier studies in Ronneby found that serum PFAS concentrations corresponded closely with residential address history, allowing residential history to be used as an accurate proxy for exposure. PFAS-ITOX uses this 'Äúnatural experiment'Äù to create a longitudinal cohort of children and evaluate whether high PFAS exposures are associated with clinical outcomes related to immunosuppression (e.g., counts of common childhood infections) and hypersensitivity (e.g., incidence of asthma). While existing studies of PFAS immunotoxicity rely on self-reported data or hospital admission records, I will use the Sk√•ne Healthcare Register, unique to southern Sweden, to identify outcomes at all levels of care, including primary care where many immune outcomes are diagnosed. The proposal's results will inform future PFAS research, provide necessary evidence for risk assessments, and provide critical information to health practitioners caring for highly-exposed individuals.