Longitudinal Associations between Prenatal Exposure to Phthalates and Steroid Hormones in Maternal Hair Samples from the SEPAGES Cohort

Abstract

We assessed phthalate-hormone associations in 382 pregnant women of the new-generation SEPAGES cohort (2014–2017, France) using improved exposure and outcome assessments. Metabolites from seven phthalate compounds and the replacement di(isononyl)cyclohexane-1,2-dicarboxylate (DINCH) were measured in within-subject pools of repeated urine samples collected at the second and third pregnancy trimesters (≈21 samples/trimester). Metabolites from five steroid hormones were measured in maternal hair samples collected at delivery, reflecting cumulative levels over the previous weeks to months. Adjusted linear regression and Bayesian weighted quantile sum (BWQS) mixture models were performed. Each doubling in third-trimester urinary mono-benzyl phthalate (MBzP) concentrations was associated with an average increase of 13.3% (95% CI: 2.65, 24.9) for ∑cortisol, 10.0% (95% CI: 0.26, 20.7) for ∑cortisone, 17.3% (95% CI: 1.67, 35.4) for 11-dehydrocorticosterone, and 16.2% (95% CI: 2.20, 32.1) for testosterone, together with a suggestive 10.5% (95% CI: −1.57, 24.1) increase in progesterone levels. Each doubling in second-trimester urinary di-isononyl phthalate (DiNP) concentrations was inversely associated with testosterone levels (−11.6%; 95% CI: −21.6, −0.31). For most hormones, a nonsignificant trend toward a positive phthalate mixture effect was observed in the third but not in the second trimester. Our study showed that exposure to some phthalate metabolites, especially MBzP, may affect adrenal and reproductive hormone levels during pregnancy.

Hair cortisol stability after 5-year storage: Insights from a sample of 17-year-old adolescents

“…Among previously published studies, some point to stability of HCC after years of storage (until 2 years) [ 5 , 6 ], while others show a decrease (until 5 years) [ [7] , [8] , [9] , [10] , [11] ]. Beyond the sample origin, two distinctive features of these studies ought to be considered (see Supplemental Table 1): those showing HCC stability were published between 2010 and 2016 and are based on immunoassays.…”

“…In our study, we examined HCC within the same samples analyzed twice, ensuring that no external factors independent of storage conditions (or analysis) could have influenced our results. This approach differentiates from investigations that explore HCC stability across various samples collected over time, as well as from those examining storage time as potential confounders within a sample, which results could be affected by a third factor [ [7] , [8] , [9] , [10] , [11] ]. There are, however, certain limitations.…”

“…A few human studies (e.g. [ [7] , [8] , [9] , [10] , [11] ]) have noted a slight decline in HCC with the passage of time between hair sample and assay. This raises the possibility that changes in absolute values of HCC may affect the relative stability of the participants’ position within the sample, which may thus affect the estimation of the “real” magnitude of their associations with other variables of interest.…”