Association of Aryl Organophosphate Flame Retardants Triphenyl Phosphate and 2-Ethylhexyl Diphenyl Phosphate with Human Blood Triglyceride and Total Cholesterol Levels

There is growing evidence that aryl organophosphate flame retardants (aryl-OPFRs) can disrupt lipid metabolism in animals. However, epidemiologic studies of this possible phenomenon are lacking. In this study, we explored the association between urinary concentrations of three aryl-OPFRs (triphenyl phosphate (TPHP), tricresyl phosphate, and 2-ethylhexyl diphenyl phosphate (EHDPP)) metabolites and plasma levels of triglyceride (TG) and total cholesterol (TC) in 259 samples of the general population by comparing with six alkylated and chlorinated OPFRs. Multivariate linear regression analyses clarified that the log-transformed TC levels appeared to increase linearly across the quartiles of 5-OH-EHDPP (p trend <0.001) and 4-OH-TPHP (p trend <0.001), with an increase of 42.2% (95% CI, 36.2% to 48.2%) and 28.4% (95% CI, 26.5% to 30.3%) for the highest versus lowest quartiles of 5-OH-EHDPP and 4-OH-TPHP, respectively. The TG level also appeared to increase linearly across the quartiles of 5-OH-EHDPP (p trend <0.001) and 4-OH-TPHP (p trend <0.001). The TG level in the highest quartile of 5-OH-EHDPP was 89.9% higher (95% CI, 84.6% to 95.2%) than that in the lowest quartile and 45.3% higher (95% CI, 40.1% to 50.7%) than that in the highest 4-OH-TPHP quartile. We for the first time found that human exposure to EHDPP and TPHP is associated with increases in human TC and TG levels.