Environment/Climate Change
Mediation of immunological markers in the association between per- and polyfluorinated substances (PFAS) and respiratory outcomes among Inuit adults Amira Aker* Amira Aker Melanie Lemire Pierre Ayotte
Objective: Per- and polyfluorinated substances (PFAS) are stable and bioaccumulative compounds. They are detected at high concentrations in the Arctic compared to the general Canadian population and have been associated with changes to the immune system in other populations and animal models. Our objective was to examine the mediating effect of immune markers on the relationship between PFAS and respiratory outcomes among Inuit adults of Nunavik.
Materials and Methods: The study included 1322 participants of the Qanuilirpitaa? 2017 Inuit Health Survey. Factor analyses were used to identify latent immunological profiles based on cytokine concentrations. Structural equation models assessed individual PFAS against the ratio of the forced expiratory volume to the lung forced vital capacity (FEV1/FVC), and the mediating effect of a Th2 response (driven by IL4, IL5, and IL13), a Th1 response (driven by IFN-γ, TNF-β, IL6, and IL1-β), and immune-related proteins (periostin, YKL40, and adiponectin).
Results: All PFAS congeners were associated with a 7-13% increase in periostin; associations with strongest with PFNA and PFOA. PFHxS and PFOS were associated with a 7-8% decrease in YKL40. YKL40 levels significantly mediated the relationship between PFOA, PFDA, PFUnDA, and PFOS and FEV1/FVC. Evidence of mediation by a Th2 response and periostin was also observed, but varied by PFAS congener.
Conclusion: There was evidence of changes in immune biomarkers by PFAS contributing to respiratory outcomes. This adds evidence to the biological mechanism of PFAS leading to adverse human health effects.