Exposure to Organophosphate esters and metabolic syndrome in adults

•Data from NHANES 2011–2014 were used to examine the associations between urinary OPE metabolites and MetS in adults.•The associations for urinary OPE metabolites and OPEs mixture varied by sex.•Certain OPE metabolites and OPEs mixture were associated with elevated odds ratio of MetS in adult men. Organophosphate esters (OPEs) are increasingly used as flame retardants and plasticizers in various products. In vivo and in vitro studies suggest that OPEs can affect metabolic health but the human evidence is lacking. We analyzed data from the U.S. National Health and Nutrition Examination Survey, 2011–2014, to examine the associations between urinary OPE metabolites and metabolic syndrome (MetS) and its components in adults. We included a total of 1157 adults aged ≥20 years who had information on urinary OPE metabolites, components of MetS and essential covariates in the current analyses. MetS was composed of hyperglycemia, hypertension, hypertriglyceridemia, low high-density cholesterol, and central obesity. Binary logistic regression and weighted quantile sum (WQS) regression were used to assess the associations of individual OPE metabolites and OPEs mixture with MetS and its components. All analyses were conducted in men and women separately. Potential effect modification by age, serum total testosterone (TT) level and menopause status were also examined via stratified analyses as well as by testing the significance of the interaction term with exposure. After adjusting for confounders, bis(2-chloroethyl) phosphate (BCEP) and bis(1,3-dichloro-2-propyl) phosphate (BDCPP) were positively associated with MetS in a dose-dependent manner (P-trend = 0.02 and 0.02 for BCEP and BDCPP, respectively) in all men. Meanwhile, increasing quartiles of DPHP was positively associated with hyperglycemia (P-trend = 0.03), but DBUP was inversely associated with central obesity (P-trend = 0.02). WQS analyses in all men found that OPEs mixture (OPEs index) was positively associated with MetS [odds ratio (OR) for OPEs index: 1.65; 95%CI :1.21, 2.24], hyperglycemia (OR:1.47; 95%CI:1.09,2.00), and central obesity (OR:1.36; 95%CI:1.01,1.83). Although there was no significant interaction between exposure and effect modifiers, stratified analyses in men suggested that significant associations were mainly limited to those aged