Associations of individual and mixture exposure to volatile organic compounds with metabolic syndrome and its components among US adults

People are exposed to various volatile organic compounds (VOCs) in their environment. Our study aims to examine the links between VOCs exposure and metabolic syndrome (MetS) and its components, as well as identify critical VOCs.In this study, we enrolled 8223 adults from the National Health and Nutrition Examination Survey (NHANES) and analyzed 15 kinds of urinary VOCs metabolites. The Spearman correlation model, generalized linear regression model, restricted cubic spline (RCS), weighted quantile sum (WQS) analysis, and Bayesian kernel machine regression (BKMR) were used to evaluate the association between individual VOC/VOCs mixture and MetS as well as its components.In generalized linear regression model, compared to the lowest quartile of urinary VOCs metabolites, the highest quartiles of urinary VOC metabolites were positively associated with MetS including N-Acetyl-S-(N-methylcarbamoyl)-l-cysteine (AMCC) (OR: 1.22, 95%CI: 1.00, 1.49), N-Acetyl-S-(2-carboxyethyl)-l-cysteine (CEMA) (OR: 1.71, 95%CI: 1.41, 2.07), N-Acetyl-S-(3-hydroxypropyl)-l-cysteine (3HPMA) (OR: 1.32, 95%CI: 1.11, 1.63), and N-Acetyl-S-(3-hydroxypropyl-1-methyl)-l-cysteine (HMPMA) (OR: 1.34, 95%CI: 1.09, 1.64). Consistent results were found in the dose-response relationship in RCS model. Results of WQS showed that VOCs mixture was positively associated with MetS (OR: 1.16, 95%CI: 1.06, 1.28), elevated WC (OR: 1.25, 95%CI: 1.13, 1.37), elevated FBG (OR: 1.24, 95%CI: 1.12, 1.37), elevated TG (OR: 1.34, 95%CI: 1.21, 1.49), and reduced HDL-C (OR: 1.20, 95%CI: 1.09, 1.33). However, the WQS index was negatively associated with elevated BP (OR: 0.81; 95%CI: 0.70, 0.94). BKMR analysis confirmed that the urinary VOCs mixture was positively associated with MetS, elevated WC, elevated TG, reduced HDL-C, elevated FBG, but negatively associated with elevated BP. CEMA was defined as the most heavily weighted chemical in the WQS and BKMR models.Our findings suggested that exposure to specific VOC or VOCs mixture is associated with the higher risk of MetS and its components, except for elevated BP.