Exposure to perfluoroalkyl substances (PFASs) – compounds widely used in industrial applications and consumer products, has been inconsistently associated with asthma, allergic diseases and airways infections in early childhood.

A new study published in Environment International investigated the effect of childhood exposure to PFASs on asthma and allergy related outcomes and on airway infections, before and during puberty.

The present study used a prospective birth cohort from the Environment and Childhood Asthma (ECA) Study. Overall, 378 children with PFAS measurements at 10 years of age (cross sectional data) and 16 years (longitudinal data) were recruited. Eight PFASs with at least 70% of measurements above the limit of quantification (LOQ) in the childs serum were included in the present study – perfluoroheptanoate (PFHpA), perfluorooctanoate (PFOA), perfluourononanoate (PFNA), perfluorodecanoate (PFDA), perfluoroundecanoate (PFUnDA), perfluorohexane sulfonate (PFHxS), perfluoroheptane sulfonate (PFHpS) and perfluorooctane sulfonate (PFOS). The PFAS levels were converted into interquartile range (IQR); perfluorooctane sulfonamide (PFOSA) detected in 60% of samples, was recoded into "not detected/detected". Sensitivity analyses evaluating the effect of extreme PFAS values and gender were performed.

In the cross-sectional data at 10 years, a positive statistically significant association was observed between PFHpA and asthma in girls. In the longitudinal data, PFNA, PFDA and PFUnDA were inversely associated with atopic dermatitis (AD) in girls, and with PFHxS in all participants and in boys. Meanwhile, PFNA and PFHpS were positively associated with rhinitis in girls and with PFOA in all participants. On the other hand, no associations were found between PFASs and lung function. PFDA was inversely associated with common cold, whereas positive correlations were found between PFHpA, PFOA, PFHpS and PFOS and lower respiratory tract infections (LRTI).

The findings provided further evidence of the immunosuppressive effect of PFASs on AD and LRTI. It was inferred that gender seems to be important for some exposure-health associations. No clear pattern in exposure-health associations was recorded with regard to exposure period or study design, with the exception of asthma.