Association between prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances and the incidence of infant and childhood respiratory infections: A systematic review.

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are persistent environmental pollutants with potential immunotoxic effects. The present systematic review evaluated the association between prenatal PFAS exposure and the incidence of respiratory infections in infants and children. For this purpose, a comprehensive literature search was conducted across the PubMed, Scopus and Cochrane Library databases following the referred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies assessing prenatal PFAS exposure and childhood respiratory infections were included. A total of six studies meeting the eligibility criteria were analyzed. Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid were the most frequently detected PFAS in maternal blood. While no significant associations were found in infancy, a greater prenatal exposure to perfluorohexane sulfonate and PFOS was linked to increased respiratory infections, particularly pneumonia and respiratory syncytial virus infections, in early childhood. Conversely, perfluorononanoic acid and perfluorodecanoic acid were associated with a reduced risk of lower respiratory tract infections and wheezing in children aged 4 to 7 years. The biological mechanisms likely involve PFAS-induced immune dysregulation, including altered cytokine responses and impaired vaccine effectiveness. The present systematic review highlights the complex role of prenatal PFAS exposure in modulating childhood respiratory health. Given the widespread presence of PFAS in the environment, regulatory policies should focus on minimizing exposure, particularly during pregnancy. Further research is required to clarify causal mechanisms and assess long-term respiratory outcomes in children.