Per- and polyfluoroalkyl substances and human health outcomes: An umbrella review of systematic reviews with meta-analyses of observational studies

Although evidence on the association between per-and polyfluoroalkyl substances (PFASs) and human health outcomes has grown exponentially, specific health outcomes and their potential associations with PFASs have not been conclusively evaluated. We conducted a comprehensive search through the databases of PubMed, Embase, and Web of Science from inception to February 29, 2024, to identify systematic reviews with meta-analyses of observational studies examining the associations between the PFASs and multiple health outcomes. The quality of included studies was evaluated using the A Measurement Tool to Assess Systematic Reviews (AMSTAR) tool, and credibility of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) criteria. The protocol of this UR had been registered in PROSPERO (CRD 42023480817). The UR identified 157 meta-analyses from 29 articles. Using the AMSTAR measurement tool, all articles were categorized as of moderate-to-high quality. Based on the GRADE assessment, significant associations between specific types of PFASs and low birth weight, tetanus vaccine response, and triglyceride levels showed high certainty of evidence. Moreover, moderate certainty of evidence with statistical significance was observed between PFASs and health outcomes including lower BMI z-score in infancy, poor sperm progressive motility, and decreased risk of preterm birth as well as preeclampsia. Fifty-two (33%) associations (e.g., PFASs and gestational hypertension, cardiovascular disease, etc) presented low certainty evidence. Additionally, eighty-five (55%) associations (e.g., PFASs with infertility, lipid metabolism, etc) presented very low certainty evidence. High certainty of evidence supported that certain PFASs were associated with the incidence of low birth weight, low efficiency of the tetanus vaccine, and low TG levels.