Low-Level Environmental Per- and Polyfluoroalkyl Substances and Preterm Birth: A Nested Case–Control Study among a Uyghur Population in Northwestern China

Evidence concerning associations between exposure to per- and polyfluoroalkyl substances (PFASs) and preterm birth is limited. We evaluated the associations of preterm birth with gestational exposures to PFAS isomers, PFAS alternatives, and legacy PFASs using a nested case–control study (384 preterm vs. 384 term births) in a northwestern China Uyghur population. Levels of 23 PFASs were determined in cord serum samples. We estimated odds ratios (ORs) and mean differences (βs) for associations between preterm birth and gestational age with an interquartile range increase in each PFAS. Stratified analyses by maternal and infant characteristics were also performed. Although PFAS concentrations were low (median, < 0.455 ng/mL), several were significantly associated with preterm birth [OR for total perfluorooctane sulfonic acid (PFOS), linear PFOS, and branched PFOS were 1.44 (95