Objective To explore the relationship between urinary perchlorate, bisphenol A, and phthalate metabolites(mPAEs), as environmental endocrine-disrupting chemicals (EDCs), and testosterone levels in women of reproductive age.

Methods A cross-sectional study design was adopted. Women aged 18-45 years were recruited from Beijing Obstetrics and Gynecology Hospital, Capital Medical University, between 2018 and 2020, and 50 mL of random midstream urine was collected from each participant. Ultra-performance liquid chromatography-tandem mass spectrometry was used to determine urinary perchlorate, nitrate, and thiocyanate. Ultra-performance liquid chromatography-triple quadrupole mass spectrometry was used to measure urinary bisphenol A and mPAEs(including monoethyl phthalate (MEP), monomethyl phthalate (MMP), monobutyl phthalate (MnBP), 2-Mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono (2-ethyl-5-oxohexyl) phthalate (MEOHP), monoisobutyl phthalate (MiBP), mono (2-ethylhexyl) phthalate (MEHP)). Testosterone levels were determined using liquid-liquid extraction combined with ultra-performance liquid chromatography-triple quadrupole tandem mass spectrometry. The associations between urinary EDCs levels and urinary testosterone were evaluated using multiple linear regression models, Bayesian kernel machine regression (BKMR), and quantile g-computation (qgcomp).

Results A total of 164 participants were included in this study. The average age was (32.0±4.8) years, and the average body mass index was (22.3±3.4) kg/m². The detection rates of the 11 tested EDCs in urine samples were all >60%. The median (P₂₅, P₇₅) concentrations of perchlorate, nitrate, and thiocyanate were 5.53 (0.71, 13.75) μg/g creatinine, 65.78 (40.54, 109.74) mg/g creatinine, and 165.01 (0.71, 377.32) μg/g creatinine, respectively. The urinary concentration of bisphenol A was 2.37 (1.44, 4.56) μg/g creatinine. Among the phthalate metabolites, MnBP had the highest level, at 137.61 (78.88, 246.17) μg/g creatinine. The detection rate of urinary testosterone was 99.39%, and the concentration was 2.64 (1.23, 5.77) μg/g creatinine. Multiple linear regression analysis showed that, compared with the Q1 group of urinary perchlorate, MnBP, and MEHP, the changes in urinary testosterone levels in the Q4 group were β, with 95% confidence intervals being -1.38 (-1.87, -0.89), 0.54 (0.01, 1.07), and 0.88 (0.36, 1.40), respectively. The qgcomp model showed that MEOHP, perchlorate, thiocyanate, MiBP, and MMP had negative weights in the overall effect of mixed exposure, whereas MEHP, MEHHP, MnBP, and MEP exhibited positive weights. The BKMR model indicated that urinary testosterone levels showed a decreasing trend with increasing overall mixed pollutant exposure.

Conclusion This study found associations between urinary perchlorate and MEHP levels as well as urinary testosterone in women of reproductive age, suggesting that exposure to EDCs may be associated with alterations in testosterone levels in women of reproductive age.