Exposure to Perfluoroalkyl Substances during Fetal Life and Pubertal Development in Boys and Girls from the Danish National Birth Cohort

Identifying Risk Factors for Levels of Per- and Polyfluoroalkyl Substances (PFAS) in the Placenta in a High-Risk Pregnancy Cohort in North Carolina

Prenatal exposure to per- and polyfluoroalkyl substances (PFAS), a ubiquitous class of chemicals, is associated with adverse outcomes such as pre-eclampsia, low infant birth weight, and later-life adiposity. The objectives of this study were to examine PFAS levels in the placenta and identify sociodemographic risk factors in a high-risk pregnancy cohort (n = 122) in Chapel Hill, North Carolina. Of concern, PFOS, PFHxS, PFHpS, and PFUnA were detected above the reporting limit in 99, 75, 55, and 49% of placentas, respectively. Maternal race/ethnicity was associated with significant differences in PFUnA levels. While the data from this high-risk cohort did not provide evidence for an association with hypertensive disorders of pregnancy, fetal growth, or gestational age, the prevalence of detectable PFAS in the placenta suggests a need to biomonitor for exposure to PFAS during pregnancy. Future research should investigate factors underlying the differences in PFAS levels in association with a mother's race/ethnicity, as well as potential effects on pregnancy and child health.

Per- and poly-fluoroalkyl substances and bone mineral density: Results from the Bayesian weighted quantile sum regression

Per- and poly-fluoroalkyl substances (PFAS) are chemicals, detected in 95% of Americans, that induce osteotoxicity and modulate hormones, thereby influencing bone health. Previous studies found associations between individual PFAS and bone mineral density in adults but did not analyze their combined effects.

OBJECTIVE

To extend weighted quantile sum (WQS) regression to a Bayesian framework (Bayesian extension of the WQS regression [BWQS]) and determine the association between a mixture of serum PFAS and mineral density in lumbar spine, total, and neck femur in 499 adults from the 2013 to 2014 National Health and Nutrition Examination Survey (NHANES).

METHODS

We used BWQS to assess the combined association of eight PFAS, as a mixture, with bone mineral density in adults. As secondary analyses, we focused on vulnerable populations (men over 50 years and postmenopausal women). Analyses were adjusted for sociodemographic factors. Sensitivity analyses included bone mineral density associations with individual compounds and results from WQS regressions.

RESULTS

The mean age was 55 years old (SD = 1) with average spine, total, and neck femur mineral densities of 1.01 (SD = 0.01), 0.95 (SD = 0.01), and 0.78 (SD = 0.01) gm/cm2, respectively. PFAS mixture levels showed no evidence of association with mineral density (spine: β = -0.004; 95% credible interval [CrI] = -0.04, 0.04; total femur: β = 0.002; 95% CrI = -0.04, 0.05; femur neck: β = 0.005; 95%CrI = -0.03, 0.04) in the overall population. Results were also null in vulnerable populations. Findings were consistent across sensitivity analyses.

CONCLUSIONS

We introduced a Bayesian extension of WQS and found no evidence of the association between PFAS mixture and bone mineral density.

The levelling-off of the secular trend of age at menarche among Italian girls

OBJECTIVE

The main aim of this study was to verify whether the secular trend stopped in Italy by comparing the results of a 1990-2000 birth cohort versus a 1980-1990 birth cohort of Italian young women. The results were used to speculate about age at menarche as adaptive response to non-genetic factors.

METHODS

In 2016, a study was set on 413, 18-to-26 year-old women (1990-2000 birth cohort) attending two Italian Universities by web-based, self-reported questionnaires. Previously in 2000, a research including 3,783 high school female students (1980-1990 birth cohort) was led. The age at menarche distribution was performed by Kaplan-Meier analysis. The comparison between the findings of the two birth cohorts was performed by Wilcoxon sum-rank test. Mixed models analysis was applied to evaluate the effect of cohort and socio-economic status on age at menarche.

RESULTS

1990-2000 cohort's age at menarche median was 12.44y (95%CI 12.37; 12.59y). There was no significant difference with age at menarche of the previous cohort (p = 0.56). Consistently, the advance of age at menarche in comparison to the mothers' one was not significantly different between the two cohorts (-0.27y±0.10y vs -0.25y±0.03y, p = 0.33). The socio-economic level was not significantly associated with menarcheal age.

CONCLUSIONS

The findings of this study confirm that, like in other developed countries, the advance of age at menarche has stopped in Italy, consistently with the stop of the improvement of socio-economic conditions. Further studies are needed to explore the differential effect of each non-genetic factor to outline future scenarios of human sexual maturation.

TRIAL REGISTRATION

the Comitato Etico per la Sperimentazione Clinica (CESC) della Provincia di Padova of the Veneto Region (Italy), n°3993/U16/16.

Efficient Reductive Destruction of Perfluoroalkyl Substances under Self-Assembled Micelle Confinement

Recently, perfluoroalkyl substances (PFASs) have received great attention from both academia and the industry due to their persistence and health risks. Here, we developed a simple ternary self-assembled micelle composite, consisting of a photosensitive substance (indole acetic acid, IAA), cationic surfactant (cetyltrimethylammonium bromide), and contaminant (PFAS). Owing to the rapid hydrated electron transfer from IAA to the PFAS in the micelle, the PFAS degradation and defluorination were greatly enhanced even under ambient conditions. After 2.5 h UV irradiation, the perfluorooctanoic acid (PFOA) concentration decreased from 10 mg L^-1 to ∼60 ng L^-1, which is below the drinking water health advisory level of the United States Environmental Protection Agency for the combined concentration of PFOA and perfluorooctane sulfonate (70 ng L^-1). Meanwhile, the dissolved organic carbon content of the reaction solution was also reduced to ∼3 mg L^-1 due to the quick settlement and automatic separation of the micelle. Furthermore, the newly developed composite was also adaptable to a wide pH range (pH 4-8), attributing to the barrier created by the ternary micelle system. This novel self-assembly method is expected to directly treat industrial PFAS-containing wastewater or PFAS-enriched concentrates derived from adsorption processes. The conceptually new advanced reduction technique represents a major breakthrough toward PFAS rapid destruction and efficient usage of hydrated electrons and might also shed light on other environmental applications.

Prenatal exposure to perfluorodecanoic acid is associated with lower circulating concentration of adrenal steroid metabolites during mini puberty in human female infants. The Odense Child Cohort

BACKGROUND

Fetal programming of the endocrine system may be affected by exposure to perfluoroalkyl substances (PFAAs), as they easily cross the placental barrier. In vitro studies suggest that PFAAs may disrupt steroidogenesis. "Mini puberty" refers to a transient surge in circulating androgens, androgen precursors, and gonadotropins in infant girls and boys within the first postnatal months. We hypothesize that prenatal PFAA exposure may decrease the concentrations of androgens in mini puberty.

OBJECTIVES

To investigate associations between maternal serum PFAA concentrations in early pregnancy and serum concentrations of androgens, their precursors, and gonadotropins during mini puberty in infancy.

METHODS

In the prospective Odense Child Cohort, maternal pregnancy serum concentrations of five PFAAs: Perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were measured at median gestational week 12 (IQR: 10, 15) in 1628 women. Among these, offspring serum concentrations of dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulfate (DHEAS), androstenedione, 17-hydroxyprogesterone (17-OHP), testosterone, luteinizing (LH) and follicle stimulating hormones (FSH) were measured in 373 children (44% girls; 56% boys) at a mean age of 3.9 (±0.9 SD) months. Multivariate linear regression models were performed to estimate associations.

RESULTS

A two-fold increase in maternal PFDA concentration was associated with a reduction in DHEA concentration by -19.6% (95% CI: -32.9%, -3.8%) in girls. In girls, also, the androstenedione and DHEAS concentrations were decreased, albeit non-significantly (p < 0.11), with a two-fold increase in maternal PFDA concentration. In boys, no significant association was found between PFAAs and concentrations of androgens, their precursors, and gonadotropins during mini puberty.

CONCLUSION

Prenatal PFDA exposure was associated with significantly lower serum DHEA concentrations and possibly also with lower androstenedione and DHEAS concentrations in female infants at mini puberty. The clinical significance of these findings remains to be elucidated.

Perfluoroalkyl Substances and Maternal Thyroid Hormones in Early Pregnancy; Findings in the Danish National Birth Cohort

BACKGROUND

Maternal thyroid hormones are essential for fetal brain development in early gestation. Perfluoroalkyl substances (PFASs)-widespread and persistent pollutants-have been suggested to interfere with maternal thyroid hormones in the second or third trimesters, but evidence for an association in the early pregnancy period is sparse.

OBJECTIVES

Our goal was to evaluate the gestational-week specific associations of maternal thyroid-stimulating hormone (TSH) and free thyroxine (fT4) levels with plasma concentrations of six PFAS chemicals in the first and second pregnancy trimester.

METHODS

A cross-sectional analysis was conducted using 1,366 maternal blood samples collected between gestational weeks (GWs) 5 and 19 (median, 8 gestational weeks) in the Danish National Birth Cohort (DNBC) during 1996-2002. We estimated the percentage changes of serum TSH and fT4 levels according to concentrations (in nanograms per milliliter) of six PFAS chemicals modeled as per interquartile range (IQR) increase or by exposure quartiles. Moreover, we contrasted the estimated week-specific TSH or fT4 levels by PFAS quartile and estimated ORs for binary high or low TSH and fT4 status based on the week-specific distribution according to IQR increase of PFAS.

RESULTS

TSH levels followed a U-curve trend in early pregnancy with a nadir at GW10, whereas fT4 levels were less fluctuated in the samples. There were no apparent associations between any of the PFASs and changes of average TSH or fT4 levels in total samples. In gestational-week-specific analyses, we found that the estimated TSH values were higher among the highest perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonate (PFHxS), and perfluoroheptane sulfonate (PFHpS) quartiles compared with the lower quartiles from GW5 to GW10, but the difference became null or even reversed after GW10. For binary outcomes, perfluorodecanoic acid (PFDA) was associated with high fT4 status before GW10 [OR=1.46 (95% CI: 1.04, 2.05)].

CONCLUSIONS

We observed some gestational-week-specific associations between high exposure to several PFAS and TSH level in early gestations. Further research of the biology and the potential clinical impact regarding thyroid hormones disruptions in early pregnancy is needed. https://doi.org/10.1289/EHP5482.