Prenatal exposure to perfluoroalkyl substances and immune and respiratory outcomes

Prenatal exposure to perfluoroalkyl substances (PFAS) may be associated with impaired immune and respiratory health during childhood but the evidence is scarce and inconsistent. We studied the association between prenatal PFAS exposure and immune and respiratory health up to age 7 years in the Spanish INMA birth cohort (n=1188). We assessed perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and perfluorononanoate (PFNA) in maternal plasma samples. Mothers reported the occurrence (yes/no) of chest infections, lower respiratory tract infections, wheezing, asthma, and eczema in the previous 12 months at 1.5 and 4 years of the child and at 7 years. At 4 and 7 years lung function was assessed using spirometry tests. The most abundant PFAS were PFOS (mean: 5.80 ng/mL) and PFOA (mean: 2.31 ng/mL). At any age, the relative risks (RR) of asthma decreased per each doubling in concentration of PFNA (RR: 0.75 [95% CI, 0.57 to 0.97]), particularly in boys. The RR of eczema at any age decreased per every doubling in PFOS concentration [RR: 0.86 [0.75 to 0.98]). At 4 years, the odds of chest infections and eczema decreased with increasing prenatal PFNA exposure; at 7 years, the odds of wheeze decreased with increasing PFOS and PFNA concentrations. At 4 years, higher PFOA concentrations were associated with a lower forced vital capacity (FVC) and lower forced expiratory volume in 1 second (FEV1), although associations did not reach statistical significance. In this study population with low levels of PFAS, we found little evidence of associations of prenatal PFAS exposure with immune and respiratory outcomes until 7 years of age.