P1143 Per- and poly-fluoroalkyl substances (PFAS) exposure is associated with later occurrence of inflammatory bowel disease

Abstract

Abstract Background Environmental chemical exposures are increasingly acknowledged as risk factors for inflammatory bowel disease (IBD). Per- and poly-fluoroalkyl substances (PFAS), a large class of persistent fluorinated organic chemicals, widely used in the modern environment, may be implicated in IBD etiology, but data are conflicting. Methods We investigated the association of PFAS mixture concentrations in pre-diagnostic serum with adult-onset IBD in a pilot study within the pre-clinical Proteomic Evaluation and Discovery in an IBD Cohort of Tri-service Subjects (PREDICTS) study. This is a nested case-control study of military personnel with Crohn’s disease (CD), ulcerative colitis (UC), and age-, sex-, and race-matched healthy controls with serum samples obtained at four-time points 1-10 years prior to IBD diagnosis. Using untargeted liquid-chromatography high-resolution mass spectrometry analytical approach, we conducted an untargeted metabolomic analysis and semiquantitative measurement of fluorinated compounds, including legacy PFAS and emerging PFAS chemicals. We used weighted quantile sum regression models adjusted for confounders to study the association of PFAS as a mixture with the odds of CD and UC at each time point. Results Our study sample included individuals with CD, UC, and matched healthy controls (n=25, each group, 4 samples per individual). Baseline characteristics were similar across cases and controls. We identified nine well known PFAS compounds and 27 other known fluorinated compounds. The chemical mixture of fluorinated compounds, including the known PFAS, in the serum samples within one year of diagnosis was associated with higher odds of CD and UC [odds ratio (OR) 2.13, 95% CI 1.33, 3.41, and 1.76, 95% CI 1.15, 2.68, respectively] per one unit increase in decile. These associations remained consistent for the PFAS mixture measured in serum at all four time points up to 10 years prior to diagnosis for both CD and UC (Figure). Major contributors to the overall mixture indices included legacy PFAS, as well as emerging PFAS chemicals. Conclusion We observed a substantial increase in the odds of CD and UC among individuals with higher serum PFAS mixture levels up to 10 years prior to diagnosis. Studies to understand underlying mechanisms are ongoing.