Urinary BPA and Phthalate Metabolite Concentrations and Plasma Vitamin D Levels in Pregnant Women: A Repeated Measures Analysis

Abstract

Background:In addition to its well-established role in maintaining skeletal health, vitamin D has essential regulatory functions in female reproductive and pregnancy outcomes. Phthalates and bisphenol A (BPA) are endocrine disruptors, and previous research has suggested that these chemical agents may disrupt circulating levels of total 25(OH)D in adults.Objectives:We investigated the relationships between repeated measures of urinary phthalate metabolites and BPA and circulating total 25(OH)D in a prospective cohort of pregnant women.Methods:The present study population includes participants (n=477) in a nested case–control study of preterm birth drawn from a prospective birth cohort of pregnant women at Brigham and Women’s Hospital in Boston, Massachusetts. Urine and blood samples were collected for biomarker measurements at median 10 wk and 26 wk of gestation.Results:In repeated measures analysis, we observed that an interquartile range (IQR) increase in urinary mono-3-carboxypropyl phthalate (MCPP) was associated with a 4.48% decrease [95% confidence interval (CI): −7.37, −1.58] in total 25(OH)D. We also detected inverse associations for metabolites of di(2-ethylhexyl) phthalate (DEHP) [percent difference (%normalΔ)=−2.83 to −2.16]. For BPA, we observed a nonsignificant inverse association with total 25(OH)D in the overall population. Our sensitivity analysis revealed that the associations for some metabolites (e.g., MEHP) varied by race/ethnicity, which may reflect potential differences in susceptibility. In agreement with findings from repeated measures analysis, we reported that DEHP metabolites and BPA were significantly associated with an approximate 20% increase in the odds of vitamin D deficiency (≤20 ng/mL) [odds ratio (95% CI): 1.19 (1.06, 1.35) for molar sum of DEHP metabolites and 1.22 (1.01, 1.47) for BPA] at median 10 wk and 26 wk, respectively.Conclusions:Our results provide suggestive evidence of the potential for environmental exposure to phthalates and/or BPA to disrupt circulating vitamin D levels in pregnancy. https://doi.org/10.1289/EHP1178

Endocrine Disrupting Chemicals and Type 1 Diabetes

“…Johns et al [130] in a cross-sectional study including 4724 adults reported an inverse association between total serum 25(OH)D and both urinary levels of DEHP metabolites in the overall population and urinary BPA in women. The same negative correlation between urinary phthalate metabolites and BPA and circulating total 25(OH)D was demonstrated also in a large prospective cohort of 477 pregnant women [131]. Finally, since PFAS were associated with altered sex steroid [132] and thyroid hormone levels [133] it was hypothesized that they may also affect vitamin D metabolism.…”

Exposure indices for phthalates and bisphenol A and their potential use in epidemiological studies

“…To the best of our knowledge, only Cantonwine D et al 46 and Johns LE et al 47 have studied prenatal exposure to BPA. Cantonwine report an average phthalate concentration of 1.95µg/g creatinine and a maximum value of 7.47µg/g creatinine.…”

Systematic review and quality ranking of studies of two phthalate metabolites and anogenital distance, bone health, inflammation, and oxidative stress

“…Four cross-sectional studies examined measures related to bone health: two measured levels of 25-hydroxyvitamin D (25(OH)D, the circulating measure of vitamin D; Johns et al 2016;Johns et al 2017), and two measured bone mineral density (BMD; Min and Min 2014; DeFlorio-Barker and Turyk 2016). All four studies were high quality: the DB percentage scores ranged from 89 to 100% (16 to 18 of a possible 18 points).…”

“…The studies measured both MEP and MiBP in adults in the United States; three of the four used NHANES data (Min and Min 2014;DeFlorio-Barker and Turyk 2016;Johns et al 2016). Three studies included only women (Min and Min 2014;DeFlorio-Barker and Turyk 2016;Johns et al 2017) and two of the three included only postmenopausal women (DeFlorio-Barker and Turyk 2016; Min and Min 2014).…”