Background High-sensitivity C-reactive protein (hs-CRP) is a sensitive biomarker for cardiovascular disease (CVD) and can independently predict the risk of cardiovascular events. Although the association between per- and polyfluoroalkyl substances (PFAS) exposure and CVD risk has been widely reported, studies on the association between hs-CRP and PFAS remain limited.

Objective To investigate the association between PFAS and hs-CRP levels, to provide a scientific basis for early identification and prevention of environment-related cardiovascular events.

Methods This study utilized data from the National Health and Nutrition Examination Survey (NHANES) database (2015–2018). Based on predefined inclusion and exclusion criteria, a total of 3219 participants were included for subsequent analysis. Five PFAS with detection rates exceeding 90% were selected as exposure factors and log-transformed (lnPFAS) for subsequent analysis, including perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorodecanoic acid (PFDA). After selecting potential confounders through a change-in-estimate approach, logistic regression was employed to examine the effects of individual PFAS on serum hs-CRP level. Additionally, quantile g-computation and Bayesian kernel machine regression (BKMR) were applied to assess the combined effects of PFAS mixtures on hs-CRP.

Results The study included 3219 participants with a mean age of (50.4±17.6) years, of whom 1554 (48.28%) were male. The median concentrations of the five PFAS compounds were: 1.20 ng·mL⁻¹ (PFHxS), 0.50 ng·mL⁻¹ (PFNA), 1.50 ng·mL⁻¹ (PFOA), 5.20 ng·mL⁻¹ (PFOS), and 0.20 ng·mL⁻¹ (PFDA). The Wilcoxon rank-sum tests revealed statistically significant differences between the elevated serum hs-CRP (≥2 mg·L⁻¹) and normal (<2 mg·L⁻¹) groups for all five PFAS compounds (PFHxS: P=0.005; PFNA: P=0.009; PFOA: P<0.001; PFOS: P<0.001; PFDA: P<0.001). After adjusting for potential confounders, the analysis of individual PFAS exposure demonstrated significant negative associations between serum hs-CRP levels and both ln-PFOS (OR: 0.87; 95%CI: 0.79, 0.96; P=0.0036) and lnPFDA (OR: 0.78; 95%CI: 0.71, 0.86; P < 0.001). The joint effect analysis using quantile g-computation revealed an overall inverse association between PFAS mixtures and hs-CRP, with lnPFDA emerging as a primary contributor; an similar association was observed in males, but not significant in females. Further evaluation through BKMR showed that when PFAS mixture concentrations reached or exceeded P₇₀, their combined effect on hs-CRP became significantly lower than when all PFAS concentrations were at P₅₀, establishing a clear negative dose-response relationship.

Conclusion The mixed exposure to PFAS showed a significant negative joint effect on serum hs-CRP levels, with PFDA being the key component contributing to this combined effect. Future prospective cohort studies are warranted to further validate these findings and elucidate the underlying mechanisms involved.