Associations between organophosphate esters and sex hormones among 6–19-year old children and adolescents in NHANES 2013–2014

•Children and adolescents are exposed to organophosphate ester (OPEs) at a disproportionate higher level.•Exposure to OPEs, either individually or as a mixture, was associated with decreased levels of certain sex steroid hormones and increased levels of sex hormone binding globulin in adolescents or pubertal individuals, with the associations presenting somewhat sex-dependent pattern.•The associations between OPE metabolites and sex hormones in children or prepubescent individuals were generally non-significant. Organophosphate esters (OPEs) are a class of alternative replacements for polybrominated diphenyl ethers. In vitro and in vivo studies suggested that OPEs may disrupt the homeostasis of sex steroid hormones. However, human evidence in children and adolescents is limited. We conducted a cross-sectional analysis of the associations between OPE biomarkers and sex steroid hormones among children (6–11 years) and adolescents (12–19 years) in the U.S. National Health and Nutrition Examination Survey, 2013–2014. Participants aged 6–19 years who had available data on urinary OPE metabolites, serum sex hormones [total testosterone (TT), estradiol (E2)] and sex hormone binding globulin (SHBG) were included (n = 544). Free androgen index (FAI) calculated as TT divided by SHBG and a ratio of TT to E2 (TT/E2) were generated. Five urinary OPE metabolites were examined. A constructed puberty status was defined as either high steroid hormone levels (TT ≥ 50 ng/dL in males and E2 ≥ 20 pg/ml in females) or onset of menarche. Multiple linear regression and weighted quantile sum (WQS) regression analyses stratified by sex-age and sex-puberty-status groups were conducted to examine the associations of OPE metabolites and its mixture with sex hormone levels. After adjusting for covariates, dibutyl phosphate (DBUP) and dibutyl phosphate (DPHP) were significantly inversely associated with TT (or FAI) and E2; DBUP was negatively associated with SHBG; and DPHP was positively associated with SHBG and TT/E2 in female adolescents. In male adolescents, we observed monotonic negative associations of bis(1,3-dichloro-2-propyl) phosphate (BDCPP), DBUP or DPHP with TT (or FAI) and E2, and positive associations of BDCPP and DPHP with SHBG. Among adolescents, the OPEs index was negatively associated with TT [WQS beta = −0.29 (95% confidence interval: −0.51, −0.07) in males and −0.15 (−0.28, −0.01) in females ], FAI [−0.46 (−0.71, −0.2) in males and −0.23 (−0.41, −0.05) in females] an