Effect of the phthalates exposure on sex steroid hormones in the US population

New alternative phthalates have been increasingly substituted for certain phthalates in some consumer products due to safety concerns. However, research on the steroidal effect of exposure to the newer replacement phthalates in the general adult population is lacking. This study aimed to examine the associations of exposure to the older generation and newer replacement phthalates with sex hormone levels in the U.S. general population. The current cross-sectional study was based on the National Health and Nutrition Examination Survey (NHANES) 2015–2016. Sixteen urinary phthalates metabolites and three serum sex hormones were measured in 1768 adults. Gender-specific associations between urinary phthalate concentrations and sex hormones were estimated by using adjusted multiple linear regression. Logistic regression was performed to calculate the risk of phthalates exposure on hormones dysfunction. Most phthalates metabolites concentrations were lower than 50 ng/mL. MEP, MBP, MiBP, MECPP, MCOP, MEHHP, MEOHP were higher than others, suggesting that new alternative DEP, DBP, and DiNP were exposed at high levels in daily life while DINCH was at a low level. Phthalates exposure was associated with decreased testosterone levels and increased estradiol and SHBG in total samples. Testosterone level was negatively associated with MnBP (β: −0.05, 95% CI: −0.09, 0), MEOHP (β:−0.05, 95% CI:−0.09,−0.01), MEHHP (β:−0.04, 95% CI:−0.08,0), MECPP (β:−0.07, 95% CI:−0.11,−0.03), MEP (β: −0.03, 95% CI: −0.06, 0), MiBP (β: −0.05, 95% CI: −0.10, −0.01) in males; ln-transformed estradiol were increased by 0.18 pg/mL (95% CI: 0.05,0.31), 0.15 pg/mL (95% CI: 0.01,0.29) with each 1 ln-concentration increase in MEHP and MNP, respectively, in females. Our results suggest that phthalates exposure may disturb the hormone homeostasis in adults. The safe alternative should be used with caution in industrial production in the future and the need for further research into the safety of the new alternative replacements is necessary. [Display omitted] •We evaluated the effect of phthalates exposure on the sex steroid hormones in adults.•Those phthalates that have been banned by the US government are still presenting high levels of load in the human body.•Findings indicate that phthalate replacements may not be safer than their previous counterpart and still hormone activators.