Racial and ethnic variations in phthalate metabolite concentration changes across full-term pregnancies

Temporal trends in phthalate metabolite exposure of girls in the United States across sociodemographic factors and intersectional social identities: National Health and Nutrition Examination Survey (NHANES) 2001-2018

BACKGROUND

Exposure to phthalates during the pubertal window is linked to an increased risk of chronic diseases. Understanding temporal trends in exposure can inform public health initiatives.

OBJECTIVE

Characterize temporal trends in phthalate metabolite levels in adolescent girls overall and by sociodemographic characteristics.

METHODS

We used the cross-sectional data from each cycle of NHANES from years 2001-2018. We included participants aged 8-14 years who had at least one urinary measurement of the selected 12 phthalate metabolites within the study period (n = 2063). We used multivariable linear regression to assess temporal trends for selected individual phthalate metabolite concentrations (ng/ml) and source groupings of parent metabolites (sum low and high molecular weight phthalates; ∑LMW and ∑HMW), overall and by sociodemographic characteristics (race/ethnicity), nativity, socioeconomic status (SES), intersection of race/ethnicity-SES) to assess for modification.

RESULTS

Overall, levels of ∑HMW and ∑LMW declined between 2001 and 2018; however, only ∑LMW consistently differed by all sociodemographic characteristics. Trends in ∑LMW concentration were significantly higher across all racial/ethnic groups, ranging from an average of 35% (Other Hispanic) to 65% (Mexican American and non-Hispanic Black) higher than non-Hispanic White (all p-values <0.0001). Compared to non-Hispanic White, a significant decrease in MiBP concentrations was observed for non-Hispanic Black (15% decrease βSpline = -0.16, p < 0.0001) and Other Hispanic (28% decrease, βSpline = -0.33, p = 0.01) in 2011-2018 versus 2001-2010. Summary and individual LMW metabolite phthalate concentrations were 11%-49% higher among girls with low vs. high SES. LMW metabolites MBP and MiBP were on average 22% and 35% higher, respectively, among foreign-born vs. U.S.-born girls. Compared to non-Hispanic Whites, all racial/ethnic groups had statistically significant higher trends in ∑LMW concentrations irrespective of SES.

SIGNIFICANCE

Girls identifying with a historically disadvantaged racial/ethnic groups exhibited elevated ∑LMW concentrations irrespective of SES; suggesting the need for targeted interventions to mitigate exposure among the most historically disadvantaged strata.

Maternal pre-pregnancy BMI influences the associations between bisphenol and phthalate exposures and maternal weight changes and fat accumulation

BACKGROUND

Bisphenols and phthalates are two classes of endocrine-disrupting chemicals (EDCs) thought to influence weight and adiposity. Limited research has investigated their influence on maternal weight changes, and no prior work has examined maternal fat mass. We examined the associations between exposure to these chemicals during pregnancy and multiple maternal weight and fat mass outcomes.

METHODS

This study included a sample of 318 women enrolled in a Canadian prospective pregnancy cohort. Second trimester urinary concentrations of 2 bisphenols and 12 phthalate metabolites were quantified. Self-reported and measured maternal weights and measured skinfold thicknesses were used to calculate gestational weight gain, 3-months and 3- to 5-years postpartum weight retention, late pregnancy fat mass gain, total postpartum fat mass loss, and late postpartum fat mass retention. Adjusted robust regressions examined associations between chemicals and outcomes in the entire study population and sub-groups stratified by pre-pregnancy body mass index (BMI). Bayesian kernel machine regression examined chemical mixture effects.

RESULTS

Among women with underweight or normal pre-pregnancy BMIs, MBzP was negatively associated with weight retention at 3- to 5-years postpartum (B = -0.04, 95%CI: -0.07, -0.01). Among women with overweight or obese pre-pregnancy BMIs, MEHP and MMP were positively associated with weight retention at 3-months and 3- to 5-years postpartum, respectively (B's = 0.12 to 0.63, 95%CIs: 0.02, 1.07). DEHP metabolites and MCNP were positively associated with late pregnancy fat mass gain and late postpartum fat mass retention (B's = 0.04 to 0.18, 95%CIs: 0.001, 0.32). Further, the mixture of EDCs was positively associated with late pregnancy fat mass gain.

CONCLUSION

In this cohort, pre-pregnancy BMI was a key determinant of the associations between second trimester exposure to bisphenols and phthalates and maternal weight changes and fat accumulation. Investigations of underlying physiological mechanisms, windows of susceptibility, and impacts on maternal and infant health are needed.

Impact of Skin Care Products on Phthalates and Phthalate Replacements in Children: the ECHO-FGS

BACKGROUND

Phthalates and their replacements have been implicated as developmental toxicants. Young children may be exposed to phthalates/replacements when using skin care products (SCPs).

OBJECTIVES

Our objective is to assess the associations between use of SCPs and children's urinary phthalate/replacement metabolite concentrations.

METHODS

Children (4-8 years old) from the Environmental Influences on Child Health Outcomes-Fetal Growth Study (ECHO-FGS) cohort provided spot urine samples from 2017 to 2019, and mothers were queried about children's SCP use in the past 24 h (n = 906 ). Concentrations of 16 urinary phthalate/replacement metabolites were determined by liquid chromatography-tandem mass spectrometry (n = 630 ). We used linear regression to estimate the child's use of different SCPs as individual predictors of urinary phthalate/replacement metabolites, adjusted for urinary specific gravity, age, sex assigned at birth, body mass index, and self-reported race/ethnic identity, as well as maternal education, and season of specimen collection. We created self-organizing maps (SOM) to group children into "exposure profiles" that reflect discovered patterns of use for multiple SCPs.

RESULTS

Children had lotions applied (43.0%) frequently, but "2-in-1" hair-care products (7.5%), sunscreens (5.9%), and oils (4.3%) infrequently. Use of lotions was associated with 1.17-fold [95% confidence interval (CI): 1.00, 1.34] greater mono-benzyl phthalate and oils with 2.86-fold (95% CI: 1.89, 4.31) greater monoethyl phthalate (MEP), 1.43-fold (95% CI: 1.09, 1.90) greater monobutyl phthalate (MBP), and 1.40-fold (95% CI: 1.22, 1.61) greater low-molecular-weight phthalates (LMW). Use of 2-in-1 haircare products was associated with 0.84-fold (95% CI: 0.72, 0.97) and 0.78-fold (95% CI: 0.62, 0.98) lesser mono(3-carboxypropyl) phthalate (MCPP) and MBP, respectively. Child's race/ethnic identity modified the associations of lotions with LMW, oils with MEP and LMW, sunscreen with MCPP, ointments with MEP, and hair conditioner with MCPP. SOM identified four distinct SCP-use exposure scenarios (i.e., profiles) within our population that predicted 1.09-fold (95% CI: 1.03, 1.15) greater mono-carboxy isononyl phthalate, 1.31-fold (95% CI: 0.98, 1.77) greater mono-2-ethyl-5-hydroxyhexyl terephthalate, 1.13-fold (95% CI: 0.99, 1.29) greater monoethylhexyl phthalate, and 1.04-fold (95% CI: 1.00, 1.09) greater diethylhexyl phthalate.

DISCUSSION

We found that reported SCP use was associated with urinary phthalate/replacement metabolites in young children. These results may inform policymakers, clinicians, and parents to help limit children's exposure to developmental toxicants. https://doi.org/10.1289/EHP13937.

Disrupted Prenatal Metabolism May Explain the Etiology of Suboptimal Neurodevelopment: A Focus on Phthalates and Micronutrients and their Relationship to Autism Spectrum Disorder

Pregnancy is a time of high metabolic coordination, as maternal metabolism adapts to support the growing fetus. Many of these changes are coordinated by the placenta, a critical fetal endocrine organ and the site of maternal-fetal crosstalk. Dysregulation in maternal and placental metabolism during pregnancy has been linked to adverse outcomes, including altered neurodevelopment. Autism spectrum disorder (ASD) is a neurodevelopmental disorder linked to metabolic alterations in both children and their mothers. Prenatal environmental exposures have been linked to risk of ASD through dysregulated maternal, placental, and fetal metabolism. In this review, we focus on recent studies investigating the associations between prenatal metabolism in the maternal-placental-fetal unit and the impact of prenatal environmental exposures to phthalates and micronutrients on ASD risk. By identifying the mechanisms through which phthalates and other ubiquitous endocrine disrupting chemicals influence development, and how nutritional interventions can impact those mechanisms, we can identify promising ways to prevent suboptimal neurodevelopment.

Phthalate and phthalate replacement concentrations in relationship to adiposity in a multi-racial cohort of children

BACKGROUND/OBJECTIVE

Phthalates and phthalate replacements are used in multiple everyday products, making many of them bioavailable to children. Experimental studies suggest that phthalates and their replacements may be obesogenic, however, epidemiologic studies remain inconsistent. Therefore, our objective was to examine the association between phthalates, phthalate replacements and childhood adiposity/obesity markers in children.

SUBJECTS/METHODS

A cross-sectional study was conducted in 630 racial/ethnically diverse children ages 4-8 years. Urinary oxidative metabolites of DINCH and DEHTP, three low molecular weight (LMW) phthalates, and eleven high molecular weight (HMW) phthalates were measured. Weight, height, waist circumference and % body fat were measured. Composite molar sum groups (nmol/ml) were natural log-transformed. Linear regression models adjusted for urine specific gravity, sex, age, race-ethnicity, birthweight, breastfeeding, reported activity level, mother's education and pre-pregnancy BMI.

RESULTS

All children had LMW and HMW phthalate metabolites and 88% had DINCH levels above the limit of detection. One unit higher in the log of DINCH was associated with 0.106 units lower BMI z-score [β = -0.106 (95% CI: -0.181, -0.031)], 0.119 units lower waist circumference z-score [β = -0.119 (95% CI: -0.189, -0.050)], and 0.012 units lower percent body fat [β = -0.012 (95% CI: -0.019, -0.005)]. LMW and HMW group values were not associated with adiposity/obesity.

CONCLUSIONS

We report an inverse association between child urinary DINCH levels, a non-phthalate plasticizer that has replaced DEHP in several applications, and BMI z-score, waist circumference z-score and % body fat in children. Few prior studies of phthalates and their replacements in children have been conducted in diverse populations. Moreover, DINCH has not received a great deal of attention or regulation, but it is a common exposure. In summary, understanding the ubiquitous nature of these chemical exposures and ultimately their sources will contribute to our understanding of their relationship with obesity.

Frequency of personal care product use among reproductive-aged Black individuals and associations with socio-demographic characteristics

BACKGROUND

Compared to White women, Black women in the United States are more likely to use personal care products (PCPs) with higher concentrations of endocrine-disrupting chemicals (EDCs) and harsher chemical formulations. This may contribute to differential health outcomes in Black women such as increased risk of breast cancer, cardiometabolic outcomes, adverse birth outcomes, and uterine fibroids.

OBJECTIVE

Classify distinct PCP use patterns across multiple types of products and examine how patterns vary by socio-demographic characteristics.

METHODS

The Study of Environment, Lifestyle and Fibroids is a cohort study of reproductive-aged Black individuals living around Detroit, Michigan. Using self-reported data on frequency of PCP collected between 2013-2018, we employed latent class analysis to identify distinct groups of participants with similar PCP use. Socio-demographic characteristics were compared across latent classes.

RESULTS

Among 1562 participants, we identified 6 latent classes: Lower Overall; Higher Nailcare; Higher Skincare; Moderate Overall; Higher Makeup/Haircare/Skincare; Higher Overall. Makeup and nailcare usage were the most predictive for classifying participants into groups. Participants in classes with less frequent use of all PCPs and those with only high use of nailcare products, were more likely to report lower socio-economic status (SES), be current smokers, have a body mass index of ≥35 kg/m2, and have ≥3 births. In comparison, participants in classes with average and more frequent use of PCPs were more likely to report higher SES, be non-smokers, be nulliparous, and have ever used oral contraceptives.

IMPACT STATEMENT

This study is one of the first detailed assessments of PCP usage among a large cohort of young adult Black women that considers multiple product categories including makeup, hair, skin, nail, and vaginal products. Latent class analysis was used to capture complex patterns of PCP use and identify distinct groups of individuals with similar product use. Although the latent classes are specific to this study population, the identified socio-demographic characteristics or behaviors associated with latent classes may inform targeted and impactful exposure reduction strategies in similar populations.

Recent use of consumer and personal care products and exposures to select endocrine disrupting chemicals among urban children with asthma

BACKGROUND

Emerging studies suggest that endocrine disrupting chemicals (EDCs) in personal care and other consumer products are linked with various adverse health effects, including respiratory and reproductive effects. Despite Black persons using more personal care products than other demographic groups and having a high asthma burden, little is known regarding their consumer product use patterns and associated EDC exposures.

OBJECTIVE

To examine the association between recent exposure to select EDCs with specific consumer products and behaviors in a cohort of 110 predominantly Black children with asthma, ages 8-17 years, living in Baltimore City, Maryland.

METHODS

We quantified concentrations of bisphenol A (BPA), bisphenol S (BPS), bisphenol F, two dichlorophenols, four parabens, triclosan, benzophenone-3, and triclocarban in spot urine samples. Questionnaires were used to capture recent (last 24-h) consumer product use and behaviors. Associations between EDCs and consumer product uses/behaviors were assessed using multivariable linear regression, adjusting for age, gender, race/ethnicity, and caregiver income level. Effect estimates were expressed as geometric mean ratios of biomarker concentrations of product-users vs non-users.

RESULTS

Increased concentrations to select EDCs were associated with recent use of air freshener (ratios; BPA: 1.9, 95%CI 1.4-2; BPS 1.7, 95%CI 1-2.97; propyl paraben: 3.0, 95%CI 1.6-5.6), scented candles (methyl paraben: 2.6, 95%CI 1.1-6.1), and scented carpet powder (2,5-dichlorophenol: 2.8, 95%CI 1.2-6.3). Additionally, consuming canned food was associated with some increased biomarker concentrations (ratios: BPA: 1.7, 95%CI 1.2-2.4; BPS: 2.1, 95% CI: 1.2-3.6).

SIGNIFICANCE

These findings add to the body of evidence suggesting that recent use of select consumer products in Black children contributes to exposure of chemicals of concern and could potentially inform exposure mitigation interventions. Findings have broad potential health implications for pediatric populations and Black children who may face exposure and health disparities.

IMPACT

Little is known about how children's personal care product use and consumer behaviors affect their exposures to endocrine disrupting chemicals (EDCs). This is particularly true for Black children who often experience a disparate exposure burden to many EDCs. This is a significant knowledge gap among children that are uniquely vulnerable to EDCs as they undergo critical windows of growth and development. Our findings show associations between consumer products and EDC exposures in predominantly Black children in low-income settings. Identifying EDC exposure determinants has broad health implications as many of these chemicals have been associated with adverse health risks.

PERHLs of Wisdom: Environmental Reproductive Health Literacy and Phthalates

Most tools that measure environmental health literacy are broad in nature. Researchers have now developed a tool specific to phthalate awareness and behaviors as they relate to reproductive health.

Risk perception and use of personal care products by race and ethnicity among a diverse population

Personal care products can contain phthalates, parabens and other endocrine-disrupting chemicals. However, information on perception of risks from personal care product use and how use varies by race and ethnicity is limited. We evaluated differences in personal care product use and risk perception in a diverse sample of participants recruited from a US college campus and online. A self-administered questionnaire captured information on sociodemographic factors, personal care product use trends and perception of risk associated with them. Pearson's chi-square and Fisher's exact tests were used to determine differences in personal care product use and risk perception by race and ethnicity. Ordered logistic regressions were performed to measure associations between personal care product use frequency across racial/ethnic categories. Participant (n = 770) mean age was 22.8 years [standard deviation ± 6.0]. Daily use of make-up (eye = 29.3%; other = 38.0%; all = 33.7%) and skincare products (55%) was most frequently reported among Middle Eastern and North African participants. Non-Hispanic Black participants reported the highest daily use of hairstyling products (52%) and lotion (78%). Daily make-up use was more frequently reported among females (41%) than males (24.6%). Levels of agreement were similar across racial and ethnic groups, that personal care product manufacturers should be required to list all ingredients (≥87%). There were significant associations between the frequency of use of some personal care products and racial/ethnic categories when the use frequencies of participants from other racial/ethnic categories were compared to the use frequency of non-Hispanic White participants. There were significant differences in daily use frequency, levels of trust, perception of safety and health risks associated with personal care products by race and ethnicity, underscoring that there may be different sources of exposure to chemicals in personal care products by race and ethnicity.

Prenatal Exposure to Environmentally Relevant Low Dosage Dibutyl Phthalate Reduces Placental Efficiency in CD-1 Mice

Introduction

Dibutyl phthalate (DBP), a phthalate congener, is widely utilized in consumer products and medication coatings. Women of reproductive age have a significant burden of DBP exposure through consumer products, occupational exposure, and medication. Prenatal DBP exposure is associated with adverse pregnancy/fetal outcomes and cardiovascular diseases in the offspring. However, the role of fetal sex and the general mechanisms underlying DBP exposure-associated adverse pregnancy outcomes are unclear. We hypothesize that prenatal DBP exposure at an environmentally relevant low dosage adversely affects fetal-placental development and function during pregnancy in a fetal sex-specific manner.

Methods

Adult female CD-1 mice (8-10wks) were orally treated with vehicle (control) or with environmentally relevant low DBP dosages at 0.1 μg/kg/day (refer as DBP0.1) daily from 30 days before pregnancy through gestational day (GD) 18.5. Dam body mass composition was measured non-invasively using the echo-magnetic resonance imaging system. Lipid disposition in fetal labyrinth and maternal decidual area of placentas was examined using Oil Red O staining.

Results

DBP0.1 exposure did not significantly affect the body weight and adiposity of non-pregnant adult female mice nor the maternal weight gain pattern and adiposity during pregnancy in adult female mice. DBP0.1 exposure does not affect fetal weight but significantly increased the placental weight at GD18.5 (indicative of decreased placental efficiency) in a fetal sex-specific manner. We further observed that DBP0.1 significantly decreased lipid disposition in fetal labyrinth of female, but not male placentas, while it did not affect lipid disposition in maternal decidual.

Conclusions

Prenatal exposure to environmentally relevant low-dosage DBP adversely impacts the fetal-placental efficiency and lipid disposition in a fetal sex-specific manner.

The effects of inhaled pollutants on reproduction in marginalized communities: a contemporary review

Important differences in health that are closely linked with social disadvantage exist within and between countries. According to the World Health Organization, life expectancy and good health continue to increase in many parts of the world, but fail to improve in other parts of the world, indicating that differences in life expectancy and health arise due to the circumstances in which people grow, live, work, and age, and the systems put in place to deal with illness. Marginalized communities experience higher rates of certain diseases and more deaths compared to the general population, indicating a profound disparity in health status. Although several factors place marginalized communities at high risk for poor health outcomes, one important factor is exposure to air pollutants. Marginalized communities and minorities are exposed to higher levels of air pollutants than the majority population. Interestingly, a link exists between air pollutant exposure and adverse reproductive outcomes, suggesting that marginalized communities may have increased reproductive disorders due to increased exposure to air pollutants compared to the general population. This review summarizes different studies showing that marginalized communities have higher exposure to air pollutants, the types of air pollutants present in our environment, and the associations between air pollution and adverse reproductive outcomes, focusing on marginalized communities.

Development of a Phthalate Environmental Reproductive Health Literacy (PERHL) Scale

BACKGROUND

Substantial evidence exists linking phthalate exposure to adverse reproductive health outcomes. Current US federal regulations of consumer product chemicals place the onus on individuals to mitigate their exposure to phthalates, with assumptions of sufficient environmental health literacy (EHL). Few validated scales for people of reproductive age exist to evaluate phthalate-specific EHL.

OBJECTIVES

Our objective is to develop a multidimensional scale characterizing latent factors of phthalate knowledge, risk perception, and self-efficacy to inform individual-level interventions for reducing phthalate exposure.

METHODS

We distributed a survey with 31 items to 117 participants in the Environmental Reproductive and Glucose Outcomes (ERGO) cohort who gave birth within the last 5 years. Exploratory factor analysis (EFA) was used to identify underlying latent factors. Internal reliability was assessed via omega hierarchical coefficient. Average sum scores for each latent factor and the overall Phthalate Environmental Reproductive Health Literacy (PERHL) score were calculated. Associations between latent factors, overall PERHL score, and sociodemographic characteristics were explored using linear models.

RESULTS

Six latent factors were identified as follows: "Awareness of Phthalate Reproductive Health Impacts," "Uncertainty," "Protective Behavior/Risk Control," "Regulatory Interest," "Awareness of Phthalate Exposure Pathways," and "General Phthalate Knowledge." Each factor demonstrated acceptable to strong internal reliability, with coefficients ranging between 0.63 and 0.93. Non-white participants had lower scores for the "Awareness of Phthalate Reproductive Health Impacts" [β : - 0.35 , 95% confidence interval (CI): - 0.63 , - 0.07 ], "Awareness of Phthalate Exposure Pathways" (β : - 0.32 , 95% CI: - 0.57 , - 0.07 ), and "General Phthalate Knowledge" (β : - 0.36 , 95% CI: - 0.66 , - 0.06 ), but no significant difference in scores on "Uncertainty" (β : 0.17, 95% CI: - 0.16 , 0.50), "Protective Behavior/Risk Control" (β : - 0.04 , 95% CI: - 0.36 , 0.28), or "Regulatory Interest" (β : - 0.21 , 95% CI: - 0.51 , 0.09). No associations were seen for age or educational attainment and latent or sum factors.

DISCUSSION

Six latent factors were identified for the PERHL scale. Non-white race and ethnicity was associated with lower scores for knowledge-related scale factors. https://doi.org/10.1289/EHP13128.

The hair tales of women of color in Northern Manhattan: a qualitative analysis

Introduction

Exposure to endocrine disrupting chemicals (EDCs), such as phthalates, can negatively impact maternal and child health, contributing to impaired fetal growth, preterm birth, and pregnancy complications, as well as increased downstream risks of cardiometabolic disease and breast cancer. Notably, women of color (WOC) are the largest consumers of personal care products, which are a common source of EDC exposure.

Methods

The Let's Reclaim Our Ancestral Roots (Let's R.O.A.R) Pilot Study developed an educational intervention delivered during pregnancy to promote reduced use of phthalate-containing hair care products (HCPs). This mixed-methods study included: (1) a quantitative analysis and (2) a qualitative analysis of the educational sessions and the semi-structured focus groups to evaluate the factors that influenced the hair care practices and product choices of WOC at various stages of life, including their current pregnancy (hereafter referred to as the hair journey). During the sessions, participants learned about EDCs (with a focus on phthalates), the unequal burden of exposure for WOC, adverse implications of exposure, and exposure reduction strategies. Focus group sessions provided insight into participants' hair journeys from childhood to the current pregnancy and explored factors during their hair product selection process. All sessions were transcribed and imported into NVivo Version 12 for coding and thematic analysis.

Results

A total of 46 individuals were enrolled in the study, and 31 participated in an educational session. This current work synthesizes the qualitative analysis of this study. We identified two important life stages (before and after gaining agency over hair care practices and product choices) and three dominant themes related to HCP use: (1) products that impacted the hair journey, which involved all mentions of hair products, (2) factors that influenced the hair journey, which included individuals or entities that shaped participants' hair experiences, and (3) the relationship between hair and sense of self, where sense of self was defined as the alignment of one's inner and outer beauty.

Conclusion

The themes intersected and impacted the participants' hair journey. Cultural integration was a sub-theme that overlapped within the dominant themes and participants discussed the effect of traditions on their hair experiences.

Personal Care Products, Socioeconomic Status, and Endocrine-Disrupting Chemical Mixtures in Black Women

Personal care products (PCPs) are sources of exposure to endocrine-disrupting chemicals (EDCs) among women, and socioeconomic status (SES) may influence these exposures. Black women have inequitable exposure to EDCs from PCP use, but no study has investigated how exposure to EDCs through PCPs may vary by SES, independent of race. Using data from the Study of Environment, Lifestyle, and Fibroids, a cohort of reproductive-aged Black women (n = 751), we quantified associations between PCPs and urinary biomarker concentrations of EDC mixtures (i.e., phthalates, phenols, parabens) within SES groups, defined using k-modes clustering based on education, income, marital status, and employment. Information about PCP use and SES was collected through questionnaires and interviews. We used principal component analysis to characterize the EDC mixture profiles. Stratified linear regression models were fit to assess associations between PCP use and EDC mixture profiles, quantified as mean differences in PC scores, by SES group. Associations between PCP use and EDC mixture profiles varied by SES group; e.g., vaginal powder use was associated with a mixture of phenols among lower SES women, whereas this association was null for higher SES women. Findings suggest that SES influences PCP EDC exposure in Black women, which has implications for public health interventions.

Evaluating Mixtures of Urinary Phthalate Metabolites and Serum Per-/Polyfluoroalkyl Substances in Relation to Adolescent Hair Cortisol: The HOME Study

Results of toxicological studies indicate that phthalates and per-/polyfluoroalkyl substances (PFAS), 2 classes of endocrine-disrupting chemicals, may alter the functioning of the hypothalamic-pituitary-adrenocortical (HPA) axis. We evaluated the associations of urinary phthalate metabolites and serum PFAS during gestation and childhood with adolescent hair cortisol concentrations (pg/mg hair) at age 12 years, an integrative marker of HPA axis activity (n = 205 mother-child pairs; Cincinnati, Ohio; enrolled 2003-2006). We used quantile-based g-computation to estimate associations between mixtures of urinary phthalate metabolites or serum PFAS and hair cortisol. We also examined whether associations of individual phthalate metabolites or PFAS with cortisol varied by the timing of exposure. We found that a 1-quartile increase in all childhood phthalate metabolites was associated with 35% higher adolescent hair cortisol (phthalate mixture ψ = 0.13; 95% confidence interval: 0.03, 0.22); these associations were driven by monoethyl phthalate, monoisobutyl phthalate, and monobenzyl phthalate. We did not find evidence that phthalate metabolites during gestation or serum PFAS mixtures were related to adolescent hair cortisol concentrations. We found suggestive evidence that higher childhood concentrations of individual PFAS were related to higher and lower adolescent hair cortisol concentrations. Our results suggest that phthalate exposure during childhood may contribute to higher levels of chronic HPA axis activity.

Racial and Ethnic Disparities in Phthalate Exposure and Preterm Birth: A Pooled Study of Sixteen U.S. Cohorts

BACKGROUND

Phthalate exposures are ubiquitous during pregnancy and may contribute to racial and ethnic disparities in preterm birth.

OBJECTIVES

We investigated race and ethnicity in the relationship between biomarkers of phthalate exposure and preterm birth by examining: a) how hypothetical reductions in racial and ethnic disparities in phthalate metabolites might reduce the probability of preterm birth; and b) exposure-response models stratified by race and ethnicity.

METHODS

We pooled individual-level data on 6,045 pregnancies from 16 U.S. cohorts. We investigated covariate-adjusted differences in nine urinary phthalate metabolite concentrations by race and ethnicity [non-Hispanic White (White, 43%), non-Hispanic Black (Black, 13%), Hispanic/Latina (38%), and Asian/Pacific Islander (3%)]. Using g-computation, we estimated changes in the probability of preterm birth under hypothetical interventions to eliminate disparities in levels of urinary phthalate metabolites by proportionally lowering average concentrations in Black and Hispanic/Latina participants to be approximately equal to the averages in White participants. We also used race and ethnicity-stratified logistic regression to characterize associations between phthalate metabolites and preterm birth.

RESULTS

In comparison with concentrations among White participants, adjusted mean phthalate metabolite concentrations were consistently higher among Black and Hispanic/Latina participants by 23%-148% and 4%-94%, respectively. Asian/Pacific Islander participants had metabolite levels that were similar to those of White participants. Hypothetical interventions to reduce disparities in metabolite mixtures were associated with lower probabilities of preterm birth for Black [13% relative reduction; 95% confidence interval (CI): - 34 % , 8.6%] and Hispanic/Latina (9% relative reduction; 95% CI: - 19 % , 0.8%) participants. Odds ratios for preterm birth in association with phthalate metabolites demonstrated heterogeneity by race and ethnicity for two individual metabolites (mono-n-butyl and monoisobutyl phthalate), with positive associations that were larger in magnitude observed among Black or Hispanic/Latina participants.

CONCLUSIONS

Phthalate metabolite concentrations differed substantially by race and ethnicity. Our results show hypothetical interventions to reduce population-level racial and ethnic disparities in biomarkers of phthalate exposure could potentially reduce the probability of preterm birth. https://doi.org/10.1289/EHP12831.

Predictors of Phthalate Metabolites Exposure among Healthy Pregnant Women in the United States, 2010-2015

Phthalate use and the concentrations of their metabolites in humans vary by geographic region, race, ethnicity, sex, product use and other factors. Exposure during pregnancy may be associated with detrimental reproductive and developmental outcomes. No studies have evaluated the predictors of exposure to a wide range of phthalate metabolites in a large, diverse population. We examined the determinants of phthalate metabolites in a cohort of racially/ethnically diverse nulliparous pregnant women. We report on urinary metabolites of nine parent phthalates or replacement compounds-Butyl benzyl phthalate (BBzP), Diisobutyl phthalate (DiBP), Diethyl phthalate (DEP), Diisononyl phthalate (DiNP), D-n-octyl phthalate (DnOP), Di-2-ethylhexyl terephthalate (DEHTP), Di-n/i-butyl phthalate (DnBP), Di-isononyl phthalate (DiNP) and Di-(2-ethylhexyl) phthalate (DEHP) from urine collected up to three times from 953 women enrolled in the Nulliparous Mothers To Be Study. Phthalate metabolites were adjusted for specific gravity. Generalized estimating equations (GEEs) were used to identify the predictors of each metabolite. Overall predictors include age, race and ethnicity, education, BMI and clinical site of care. Women who were Non-Hispanic Black, Hispanic or Asian, obese or had lower levels of education had higher concentrations of selected metabolites. These findings indicate exposure patterns that require policies to reduce exposure in specific subgroups.

Systematic evidence mapping informs a class-based approach to assessing personal care products and pubertal timing

BACKGROUND

Personal care products (PCPs) contain many different compounds and are a source of exposure to endocrine disrupting chemicals (EDCs), including phthalates and phenols. Early-life exposure to EDCs commonly found in PCPs has been linked to earlier onset of puberty.

OBJECTIVE

To characterize the human and animal evidence on the association between puberty-related outcomes and exposure to PCPs and their chemical constituents and, if there is sufficient evidence, identify groups of chemicals and outcomes to support a systematic review for a class-based hazard or risk assessment.

METHODS

We followed the OHAT systematic review framework to characterize the human and animal evidence on the association between puberty-related health outcomes and exposure to PCPs and their chemical constituents.

RESULTS

Ninety-eight human and 299 animal studies that evaluated a total of 96 different chemicals were identified and mapped by key concepts including chemical class, data stream, and puberty-related health outcome. Among these studies, phthalates and phenols were the most well-studied chemical classes. Most of the phthalate and phenol studies examined secondary sex characteristics and changes in estradiol and testosterone levels. Studies evaluating PCP use and other chemical classes (e.g., parabens) had less data.

CONCLUSIONS

This systematic evidence map identified and mapped the published research evaluating the association between exposure to PCPs and their chemical constituents and puberty-related health outcomes. The resulting interactive visualization allows researchers to make evidence-based decisions on the available research by enabling them to search, sort, and filter the literature base of puberty-related studies by key concepts. This map can be used by researchers and regulators to prioritize and target future research and funding to reduce uncertainties and address data gaps. It also provides information to inform a class-based hazard or risk assessment on the association between phthalate and phenol exposures and puberty-related health outcomes.

Exposure to phthalate metabolites, bisphenol A, and psychosocial stress mixtures and pregnancy outcomes in the Atlanta African American maternal-child cohort

BACKGROUND

Consumer products are common sources of exposure for phthalates and bisphenol A (BPA), which disrupt the endocrine system. Psychosocial stressors have been shown to amplify the toxic effects of endocrine disruptors but, information is limited among African Americans (AAs), who experience the highest rates of adverse pregnancy outcomes and are often exposed to the highest levels of chemical and non-chemical stressors. We examined the association between an exposure mixture of phthalate metabolites, BPA, and psychosocial stressors with gestational age at delivery and birthweight for gestational age z-scores in pregnant AA women.

STUDY DESIGN

Participants were enrolled in the Atlanta African American Maternal-Child Cohort (N = 247). Concentrations of eight phthalate metabolites and BPA were measured in urine samples collected at up to two timepoints during pregnancy (8-14 weeks gestation and 20-32 weeks gestation) and were averaged. Psychosocial stressors were measured using self-reported, validated questionnaires that assessed experiences of discrimination, gendered racial stress, depression, and anxiety. Linear regression was used to estimate individual associations between stress exposures (chemical and psychosocial) and birth outcomes. We leveraged quantile g-computation was used to examine joint effects of chemical and stress exposures on gestational age at delivery (in weeks) and birthweight for gestational age z-scores.

RESULTS

A simultaneous increase in all phthalate metabolites and BPA was associated with a moderate reduction in birthweight z-scores (mean change per quartile increase = -0.22, 95% CI = -0.45, 0.0). The association between our exposure mixture and birthweight z-scores became stronger when including psychosocial stressors as additional exposures (mean change per quantile increase = -0.35, 95% CI = -0.61, -0.08). Overall, we found null associations between exposure to chemical and non-chemical stressors with gestational age at delivery.

CONCLUSIONS

In a prospective cohort of AA mother-newborn dyads, we observed that increased prenatal exposure to phthalates, BPA, and psychosocial stressors were associated with adverse pregnancy outcomes.

Variability and Longitudinal Trajectories of Phthalate and Replacement Biomarkers across Pregnancy in the Human Placenta and Phthalates Study

Human exposure to phthalates is widespread, but assessment of variability across pregnancy has been hampered by short half-lives of phthalate biomarkers and a few repeated measures in prior studies. We aimed to characterize the variability and longitudinal profiles of phthalate and replacement biomarkers across pregnancy. Within the Human Placenta and Phthalates Study, 303 pregnant women provided urine samples at up to 8 visits across gestation. Concentrations of 14 metabolites of phthalates and 4 metabolites of replacements were quantified in each sample, and subject-specific averages within each trimester were calculated. We examined variability in individual biomarker concentrations across the 8 visits, within trimesters, and across trimester-specific averages using intraclass correlation coefficients (ICCs). To explore longitudinal exposure biomarker profiles, we applied group-based trajectory modeling to trimester-specific averages over pregnancy. Pooling multiple visits into trimester-specific averages improved the ICCs for all biomarkers. Most biomarkers generally showed stable concentrations across gestation, i.e., high-, medium-, and low-concentration profiles, with small proportions of participants falling into the "high"-exposure groups. Variability over pregnancy is likely attributable to random fluctuations around a baseline exposure rather than true changes in concentrations over time.

Evaluating Neighborhood-Level Differences in Hair Product Safety by Environmental Working Group Ratings among Retailers in Boston, Massachusetts

BACKGROUND

Personal care products are a notable source of exposure to endocrine-disrupting chemicals (EDCs). Racial/ethnic differences in the use of hair products containing EDCs are reported, with women and children of color more commonly using hair products that are hormonally active and contain EDCs than other racial/ethnic groups. There is limited research examining the neighborhood-level social and economic factors that may contribute to these reported disparities.

OBJECTIVES

We aimed to examine the safety of hair products across sociodemographically diverse neighborhoods in Boston, Massachusetts.

METHODS

Eight neighborhoods were identified based on indicators of race/ethnicity and socioeconomic status (SES). We randomly selected 50 stores and collected data on the hair products for sale and their corresponding Environmental Working Group (EWG) Skin Deep hazard score. The association between neighborhood and EWG hazard category (low, moderate, high) was examined using a multinomial logistic regression.

RESULTS

A total of 14,019 hair products were identified in the eight neighborhoods. When considering products with EWG hazard scores, Roxbury, a lower income community of color, and Mission Hill, a lower income community, were reported to have a higher percentage of high-hazard hair products in comparison with Beacon Hill [12.2% (163/1,332), 11.4% (65/571) vs. 7.9% (30/382), respectively]. Differences between the safety of hair products were observed, with Roxbury and Mission Hill reporting more than a 2-fold higher risk ratio (RR) of finding hair products with high vs. low EWG scores in comparison with that of Beacon Hill [RR for Roxbury: 2.3, 95% confidence interval (CI): 1.1, 4.6; RR for Mission Hill: 2.3, 95% CI: 1.0, 5.4]. Other neighborhoods were also observed to have an increased RR in comparison with Beacon Hill, however, with 95% CIs that extended beyond the null.

DISCUSSION

Retail stores in neighborhoods with a higher percentage of residents of color and lower SES were found to be more likely to sell products with high hazard scores than stores in a higher SES and predominately non-Hispanic White neighborhood. https://doi.org/10.1289/EHP10653.

Characterizing the Contribution of Indoor Residential Phthalate and Phthalate Alternative Dust Concentrations to Internal Dose in the US General Population: An Updated Systematic Review and Meta-Analysis

Diet is the primary exposure pathway for phthalates, but relative contributions of other exposure sources are not well characterized. This study quantifies the relative contribution of indoor residential dust phthalate and phthalate alternative concentrations to total internal dose estimated from the National Health and Nutrition Examination Survey (NHANES) urinary metabolite concentrations. Specifically, median phthalate and phthalate alternative concentrations measured in residential dust were determined by updating a pre-existing systematic review and meta-analysis published in 2015 and the attributable internal dose was estimated using intake and reverse dosimetry models. Employing a predetermined search strategy, 12 studies published between January 2000 and April 2022 from Web of Science and PubMed measuring phthalates and phthalate alternatives in residential dust were identified. From the data extracted, it was estimated that dust contributed more significantly to the internal dose of low-molecular weight chemicals such as DEP and BBP when compared to high-molecular weight chemicals such as DEHTP. Additionally, findings showed that the chemical profile of residential dust is changing temporally with more phthalate alternatives being detected in the indoor environment. Future studies should seek to characterize the contribution of dust to an overall phthalate and phthalate alternative intake for individuals who have higher than normal exposures.

Douching and Genital Talc Use: Patterns of Use and Reliability of Self-reported Exposure

BACKGROUND

Feminine hygiene products contain chemicals that may be harmful to human health. Observational studies of the long-term health effects of such products largely rely on self-reported, recalled exposure. We sought to capture patterns of use over the life course and evaluate the reliability of self-reported data.

METHODS

We collected retrospective data on douching and genital talc use in the US-based Sister Study at two-time points and evaluated the consistency of reporting. At enrollment (2003-2009), participants were asked to report use in the last year and during ages 10-13. On a follow-up questionnaire (2017-2019), participants were asked about their use of douche or genital talc over their lifetimes.

RESULTS

Among 36,202 women who completed both questionnaires, 14% initially reported ever douching and 27% initially reported ever using genital talc. On the follow-up questionnaire, 51% of participants reported ever douching and 32% reported ever using genital talc. Comparisons across the two questionnaires for use in the year before enrollment showed good consistency, with 90% providing the same responses about douching and 87% providing the same responses about genital talc use. Reliability did not vary by cancer status, race and ethnicity, attained education, or age, though there was some evidence of recall bias for genital talc use among ovarian cancer survivors.

CONCLUSIONS

Classification of ever use of feminine hygiene products may be recalled with good consistency, but agreement was lower for specific time periods and trends may vary by subgroup. These potential differences warrant careful consideration in future studies.

Chemicals of concern in personal care products used by women of color in three communities of California

BACKGROUND

Personal care products (PCPs) may contain chemicals associated with adverse health effects. Prior studies found differences in product use by race/ethnicity and suggest some women are disproportionately exposed to chemicals of concern (CoCs).

OBJECTIVE

We quantified chemicals linked to cancer, reproductive or developmental harm, or endocrine disruption in PCPs used by women of color.

METHODS

We documented PCPs in stores frequented by Black, Latina, and Vietnamese women in their communities in California and CoCs on ingredient labels of 546 unique hair, skin, makeup, nail, deodorant/perfume, and intimate care products. Community partners chose 31 products for a combined targeted and suspect screen (National Institute of Standards and Technology mass spectral library search) two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOFMS) analysis to detect chemicals not on ingredient labels.

RESULTS

We found that 65% of labels included CoCs, and 74% of labels had undisclosed ingredients listed as "fragrance." The most prevalent chemicals were parabens, cyclosiloxanes, and formaldehyde releasers. GCxGC-TOFMS found additional CoCs, including fragrances, solvents, preservatives, ultraviolet filters, and contaminants.

SIGNIFICANCE

These findings contribute to awareness of potentially hazardous chemicals in PCPs, can help estimate disparities in chemical exposure, and complement research on health inequities due to chemical exposures from various contributors.

IMPACT STATEMENT

This study is one of the first detailed assessments of chemicals of concern found in various types of PCPs used by several racial/ethnic groups. We found that over half of the 546 products selected by community partners as marketed to and/or used by them contained ingredients linked to cancer, reproductive or developmental harm, or endocrine disruption. Laboratory analysis identified additional chemicals in a subset of products, including unlabeled fragrance chemicals and contaminants. Elucidating exposures to chemicals in PCPs is important for risk assessment and health inequity research.

Phthalate and bisphenol a exposures during pregnancy: Findings from the National Children's Study

Maternal exposure to phthalates and bisphenol A (BPA) during pregnancy can result in many adverse offspring health outcomes. Exposure to phthalates and BPA can vary depending on consumption of certain foods, some of which may vary by race/ethnicity. This study relates urine phthalate and BPA concentrations to sociodemographic and diet data. Concentrations of bisphenol A (BPA) and 11 phthalate metabolites were measured from spot urine at the third trimester visit of a sample of 485 pregnant women from the National Children's Study Vanguard Study Pilot data from seven U.S. cities. At the same time, food frequency questionnaires (FFQ) using the Diet*Calc software were obtained from 313 (65%) participants to assess dietary behavior. Overall, phthalate metabolites were highest among Hispanic women, particularly mBP, miBP, and mECPP, and these disparities were not explained by diet. Participants who did not attend college had higher concentrations of mBP, mBzP, mEP, and miBP, and lower mCOP. These disparities were also not explained by diet. The causes for these disparities should be further studied to reduce potential negative health outcomes associated with phthalate exposure for children of Hispanic or non-college educated women.

Concurrent Assessment of Phthalates/HEXAMOLL® DINCH Exposure and Wechsler Intelligence Scale for Children Performance in Three European Cohorts of the HBM4EU Aligned Studies

Information about the effects of phthalates and non-phthalate substitute cyclohexane-1,2-dicarboxylic acid diisononyl ester (HEXAMOLL^® DINCH) on children's neurodevelopment is limited. The aim of the present research is to evaluate the association between phthalate/HEXAMOLL^® DINCH exposure and child neurodevelopment in three European cohorts involved in HBM4EU Aligned Studies. Participating subjects were school-aged children belonging to the Northern Adriatic cohort II (NAC-II), Italy, Odense Child Cohort (OCC), Denmark, and PCB cohort, Slovakia. In each cohort, children's neurodevelopment was assessed through the Full-Scale Intelligence Quotient score (FSIQ) of the Wechsler Intelligence Scale of Children test using three different editions. The children's urine samples, collected for one point in time concurrently with the neurodevelopmental evaluation, were analyzed for several phthalates/HEXAMOLL^® DINCH biomarkers. The relation between phthalates/HEXAMOLL^® DINCH and FSIQ was explored by applying separate multiple linear regressions in each cohort. The means and standard deviations of FSIQ were 109 ± 11 (NAC-II), 98 ± 12 (OCC), and 81 ± 15 (PCB cohort). In NAC-II, direct associations between FSIQ and DEHP's biomarkers were found: 5OH-MEHP+5oxo-MEHP (β = 2.56; 95% CI 0.58-4.55; N = 270), 5OH-MEHP+5cx-MEPP (β = 2.48; 95% CI 0.47-4.49; N = 270) and 5OH-MEHP (β = 2.58; 95% CI 0.65-4.51; N = 270). On the contrary, in the OCC the relation between DEHP's biomarkers and FSIQ tended to be inverse but imprecise (p-value ≥ 0.10). No associations were found in the PCB cohort. FSIQ was not associated with HEXAMOLL^® DINCH in any cohort. In conclusion, these results do not provide evidence of an association between concurrent phthalate/DINCHHEXAMOLLR DINCH exposure and IQ in children.

Maternal Serum and Placental Metabolomes in Association with Prenatal Phthalate Exposure and Neurodevelopmental Outcomes in the MARBLES Cohort

Prenatal exposure to phthalates, a family of endocrine-disrupting plasticizers, is associated with disruption of maternal metabolism and impaired neurodevelopment. We investigated associations between prenatal phthalate exposure and alterations of both the maternal third trimester serum metabolome and the placental metabolome at birth, and associations of these with child neurodevelopmental outcomes using data and samples from the Markers of Autism Risk in Babies Learning Early Signs (MARBLES) cohort. The third trimester serum (n = 106) and placental (n = 132) metabolomes were investigated using 1H nuclear magnetic resonance spectroscopy. Children were assessed clinically for autism spectrum disorder (ASD) and cognitive development. Although none of the urinary phthalate metabolite concentrations were associated with maternal serum metabolites after adjustment for covariates, mixture analysis using quantile g-computation revealed alterations in placental metabolites with increasing concentrations of phthalate metabolites that included reduced concentrations of 2-hydoxybutyrate, carnitine, O-acetylcarnitine, glucitol, and N-acetylneuraminate. Child neurodevelopmental outcome was not associated with the third trimester serum metabolome, but it was correlated with the placental metabolome in male children only. Maternal phthalate exposure during pregnancy is associated with differences in the placental metabolome at delivery, and the placental metabolome is associated with neurodevelopmental outcomes in males in a cohort with high familial ASD risk.

Associations Between Prenatal Urinary Biomarkers of Phthalate Exposure and Preterm Birth: A Pooled Study of 16 US Cohorts

Importance

Phthalate exposure is widespread among pregnant women and may be a risk factor for preterm birth.

Objective

To investigate the prospective association between urinary biomarkers of phthalates in pregnancy and preterm birth among individuals living in the US.

Design, Setting, and Participants

Individual-level data were pooled from 16 preconception and pregnancy studies conducted in the US. Pregnant individuals who delivered between 1983 and 2018 and provided 1 or more urine samples during pregnancy were included.

Exposures

Urinary phthalate metabolites were quantified as biomarkers of phthalate exposure. Concentrations of 11 phthalate metabolites were standardized for urine dilution and mean repeated measurements across pregnancy were calculated.

Main Outcomes and Measures

Logistic regression models were used to examine the association between each phthalate metabolite with the odds of preterm birth, defined as less than 37 weeks of gestation at delivery (n = 539). Models pooled data using fixed effects and adjusted for maternal age, race and ethnicity, education, and prepregnancy body mass index. The association between the overall mixture of phthalate metabolites and preterm birth was also examined with logistic regression. G-computation, which requires certain assumptions to be considered causal, was used to estimate the association with hypothetical interventions to reduce the mixture concentrations on preterm birth.

Results

The final analytic sample included 6045 participants (mean [SD] age, 29.1 [6.1] years). Overall, 802 individuals (13.3%) were Black, 2323 (38.4%) were Hispanic/Latina, 2576 (42.6%) were White, and 328 (5.4%) had other race and ethnicity (including American Indian/Alaskan Native, Native Hawaiian, >1 racial identity, or reported as other). Most phthalate metabolites were detected in more than 96% of participants. Higher odds of preterm birth, ranging from 12% to 16%, were observed in association with an interquartile range increase in urinary concentrations of mono-n-butyl phthalate (odds ratio [OR], 1.12 [95% CI, 0.98-1.27]), mono-isobutyl phthalate (OR, 1.16 [95% CI, 1.00-1.34]), mono(2-ethyl-5-carboxypentyl) phthalate (OR, 1.16 [95% CI, 1.00-1.34]), and mono(3-carboxypropyl) phthalate (OR, 1.14 [95% CI, 1.01-1.29]). Among approximately 90 preterm births per 1000 live births in this study population, hypothetical interventions to reduce the mixture of phthalate metabolite levels by 10%, 30%, and 50% were estimated to prevent 1.8 (95% CI, 0.5-3.1), 5.9 (95% CI, 1.7-9.9), and 11.1 (95% CI, 3.6-18.3) preterm births, respectively.

Conclusions and Relevance

Results from this large US study population suggest that phthalate exposure during pregnancy may be a preventable risk factor for preterm delivery.

Identification of profiles and determinants of maternal pregnancy urinary biomarkers of phthalates and replacements in the Illinois Kids Development Study

BACKGROUND/OBJECTIVES

Pregnant women are exposed to multiple phthalates and their replacements, which are endocrine disrupting chemicals associated with adverse maternal and child health outcomes. Identifying maternal characteristics associated with phthalate/replacement exposure during pregnancy is important.

METHODS

We evaluated 13 maternal sociodemographic and lifestyle factors, enrollment year, and conception season as determinants of exposure biomarkers of phthalates and their replacements in 482 pregnant women from the Illinois Kids Development Study (I-KIDS, enrolled 2013-2018). We quantified 19 phthalate/replacement metabolites in pools of five first-morning urines collected across pregnancy. K-means clustering identified women with distinct patterns of biomarker concentrations and principal component analysis (PCA) identified principal component (PC) profiles of biomarkers that exist together. We used multivariable regression models to evaluate associations of predictors with identified k-means clusters and PCs.

RESULTS

K-means clustering identified two clusters of women: 1) low phthalate/di(2-ethylhexyl) terephthalate (∑DEHTP) and 2) high phthalate/∑DEHTP biomarker concentrations. PCA identified four PCs with loadings heaviest for biomarkers of plasticizer phthalates [di-isononyl, di-isodecyl, di-n-octyl phthalates] (PC1), of other phthalates [dibenzyl, di-n-butyl, di-iso-butyl phthalates] (PC2), of phthalate replacements [∑DEHTP, di(isononyl) cyclohexane-1,2-dicarboxylate (∑DiNCH)] (PC3), and of monoethyl phthalate [MEP] (PC4). Overall, age, marital status, income, parity, pre-pregnancy BMI, caffeine intake, enrollment year, and conception season were independently associated with k-means cluster membership and at least one PC. Additionally, race/ethnicity, education, employment, pregnancy intention, smoking status, alcohol intake, and diet were associated with at least one PC. For instance, women who conceived in the spring, summer, and/or fall months had lower odds of high phthalate/∑DEHTP cluster membership and had lower plasticizer phthalate, phthalate replacement, and MEP PC scores.

CONCLUSIONS

Conception season, enrollment year, and several sociodemographic/lifestyle factors were predictive of phthalate/replacement biomarker profiles. Future studies should corroborate these findings, with a special focus on replacements to which pregnant women are becoming increasingly exposed.

Urinary phthalate and DINCH metabolite concentrations and gradations of maternal glucose intolerance

BACKGROUND

Studies suggest a link between pregnancy phthalate exposures and gestational diabetes mellitus (GDM). Few studies have evaluated associations between phthalate biomarkers (individual or mixtures) with gradations of maternal glucose intolerance.

METHODS

In a subset of 606 women participating in LIFECODES pregnancy cohort, a combination of 50-gram 1-h non-fasting glucose load test (GLT) and 100-gram 3-h fasting oral glucose tolerance test was used to determine pregnancy glycemic status (median: 27 weeks gestation): normoglycemia (n = 136), impaired glucose tolerance (IGT) (n = 296), and GDM (n = 174). Nineteen metabolites of phthalates and their replacements were measured during each trimester. We used multivariable logistic regression models to evaluate associations between biomarkers (in quartiles) and maternal glycemic status (GDM v. normoglycemia and IGT v. normoglycemia), adjusting for potential confounders. We also used principal component analysis to evaluate associations jointly accounting for metabolites as chemical mixtures.

RESULTS

Higher 1st trimester mono-3-carboxypropyl phthalate (MCPP) was associated with decreased odds of GDM (Q4 v. Q1: 0.30; 95% CI: 0.13, 0.67) and IGT (Q4 v. Q1 OR: 0.37; 95% CI: 0.17, 0.79). Higher 2nd trimester mono-isobutyl phthalate (MiBP) was associated with increased IGT (Q4 v. Q1 OR: 2.07; 95% CI: 1.06, 4.07), and 2nd trimester mono-3-hydroxybutyl phthalate (MHBP) was non-monotonically associated with increased GDM (Q2 v. Q1 OR: 3.21; 95% CI: 1.54, 6.87). Mixture analyses showed similar associations (Q4 v. Q1 for 2nd trimester dibutyl phthalates metabotlites mixtures OR: 2.08; 95% CI: 1.04, 4.22).

CONCLUSION

Some phthalate biomarkershad trimester-specific associations with glycemic outcomes, with long and short term health implications.

A Children's Health Perspective on Nano- and Microplastics

BACKGROUND

Pregnancy, infancy, and childhood are sensitive windows for environmental exposures. Yet the health effects of exposure to nano- and microplastics (NMPs) remain largely uninvestigated or unknown. Although plastic chemicals are a well-established research topic, the impacts of plastic particles are unexplored, especially with regard to early life exposures.

OBJECTIVES

This commentary aims to summarize the knowns and unknowns around child- and pregnancy-relevant exposures to NMPs via inhalation, placental transfer, ingestion and breastmilk, and dermal absorption.

METHODS

A comprehensive literature search to map the state of the science on NMPs found 37 primary research articles on the health relevance of NMPs during early life and revealed major knowledge gaps in the field. We discuss opportunities and challenges for quantifying child-specific exposures (e.g., NMPs in breastmilk or infant formula) and health effects, in light of global inequalities in baby bottle use, consumption of packaged foods, air pollution, hazardous plastic disposal, and regulatory safeguards. We also summarize research needs for linking child health and NMP exposures and address the unknowns in the context of public health action.

DISCUSSION

Few studies have addressed child-specific sources of exposure, and exposure estimates currently rely on generic assumptions rather than empirical measurements. Furthermore, toxicological research on NMPs has not specifically focused on child health, yet children's immature defense mechanisms make them particularly vulnerable. Apart from few studies investigating the placental transfer of NMPs, the physicochemical properties (e.g., polymer, size, shape, charge) driving the absorption, biodistribution, and elimination in early life have yet to be benchmarked. Accordingly, the evidence base regarding the potential health impacts of NMPs in early life remains sparse. Based on the evidence to date, we provide recommendations to fill research gaps, stimulate policymakers and industry to address the safety of NMPs, and point to opportunities for families to reduce early life exposures to plastic. https://doi.org/10.1289/EHP9086.

Use of hair products in relation to ovarian cancer risk

We evaluated whether hair products, which may contain carcinogens and endocrine disruptors that can be absorbed into the bloodstream, are related to ovarian cancer incidence in a prospective cohort. After excluding women with a history of ovarian cancer or bilateral oophorectomy, 40 559 Sister Study participants ages 35-74 at enrollment (2003-2009) were included. Participants completed questionnaires on hair product use, including hair dyes, straighteners/relaxers and permanents/body waves, in the past 12 months. Cox regression was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between hair products and incident ovarian cancer. We assessed associations stratified by tumor type (serous, non-serous). Over a mean follow-up of 10 years, 241 women were diagnosed with ovarian cancer. Ever use of any of the examined hair products during the past year was not associated with ovarian cancer risk. However, frequent use (>4 times/year) of straighteners/relaxers or pressing products in the past year was associated with an increased risk of ovarian cancer (HR = 2.19, 95% CI: 1.12-4.27). Ever use of permanent hair dye was positively associated with non-serous (HR = 1.94, 95% CI 1.12-3.37), but inversely associated with serous (HR = 0.65, 95% CI: 0.43-0.99) tumors (p-for-heterogeneity = 0.002). Our novel findings suggest that frequent use of hair straighteners/relaxers or pressing products, which are primarily used by African American/Black women, and possibly permanent hair dye, may be associated with the occurrence of ovarian cancers.

PERTURBED FACTOR ANALYSIS: ACCOUNTING FOR GROUP DIFFERENCES IN EXPOSURE PROFILES

In this article we investigate group differences in phthalate exposure profiles using NHANES data. Phthalates are a family of industrial chemicals used in plastics and as solvents. There is increasing evidence of adverse health effects of exposure to phthalates on reproduction and neurodevelopment and concern about racial disparities in exposure. We would like to identify a single set of low-dimensional factors summarizing exposure to different chemicals, while allowing differences across groups. Improving on current multigroup additive factor models, we propose a class of Perturbed Factor Analysis (PFA) models that assume a common factor structure after perturbing the data via multiplication by a group-specific matrix. Bayesian inference algorithms are defined using a matrix normal hierarchical model for the perturbation matrices. The resulting model is just as flexible as current approaches in allowing arbitrarily large differences across groups but has substantial advantages that we illustrate in simulation studies. Applying PFA to NHANES data, we learn common factors summarizing exposures to phthalates, while showing clear differences across groups.

Socioeconomic and racial/ethnic differences in use of endocrine-disrupting chemical-associated personal care product categories among pregnant women

Personal care products (PCPs) are important and modifiable sources of exposure to endocrine disrupting chemicals (EDCs). Research is limited on how EDC-associated PCP use differs by race/ethnicity and socioeconomic status (SES), particularly during the sensitive period of pregnancy. We investigated differences in PCP use by race/ethnicity and SES among 497 participants in the LIFECODES pregnancy cohort (Boston, Massachusetts). Participants self-reported race/ethnicity, SES indicators (maternal education; insurance status), and recent PCP use via questionnaire at ≤4 prenatal visits. We evaluated trimester-specific differences in use of individual PCP categories by race/ethnicity and SES indicators. We used Poisson regression to estimate trimester-specific mean total product categories used by race/ethnicity and SES indicators. In the first trimester, compared to non-Hispanic White women, Hispanic women reported higher use of hair gel (45% vs. 28%), perfume (75% vs. 39%), and "other" hair products (37% vs. 19%). Compared to women with a college degree, women without a college degree reported higher use of perfume (79% vs. 41%) and bar soap (74% vs. 56%); patterns were similar for insurance status. The estimated mean total product categories used was significantly lower in Asian compared to non-Hispanic White women in all trimesters (e.g., Trimester 1: 4.8 vs. 6.7 categories; p<0.001). Patterns of PCP use differed by race/ethnicity and SES, with implications for potentially modifiable differential EDC exposure and associated pregnancy outcomes.

Racial/Ethnic Disparities in Pregnancy and Prenatal Exposure to Endocrine-Disrupting Chemicals Commonly Used in Personal Care Products

PURPOSE OF REVIEW

Endocrine-disrupting chemical (EDC) exposure during pregnancy is linked to adverse maternal and child health outcomes that are racially/ethnically disparate. Personal care products (PCP) are one source of EDCs where differences in racial/ethnic patterns of use exist. We assessed the literature for racial/ethnic disparities in pregnancy and prenatal PCP chemical exposures.

RECENT FINDINGS

Only 3 studies explicitly examined racial/ethnic disparities in pregnancy and prenatal exposure to PCP-associated EDCs. Fifty-three articles from 12 cohorts presented EDC concentrations stratified by race/ethnicity or among homogenous US minority populations. Studies reported on phthalates and phenols. Higher phthalate metabolites and paraben concentrations were observed for pregnant non-Hispanic Black and Hispanic women. Higher concentrations of benzophenone-3 were observed in non-Hispanic White women; results were inconsistent for triclosan. This review highlights need for future research examining pregnancy and prenatal PCP-associated EDCs disparities to understand and reduce racial/ethnic disparities in maternal and child health.

Hair product use and breast cancer incidence in the Black Women's Health Study

Hair relaxers and leave-in conditioners and oils, commonly used by Black/African American women, may contain estrogens or estrogen-disrupting compounds. Thus, their use may contribute to breast cancer risk. Results of the few previous studies on this topic are inconsistent. We assessed the relation of hair relaxer and leave-in conditioner use to breast cancer incidence in the Black Women's Health Study, a nationwide prospective study of Black women. Among 50 543 women followed from 1997 to 2017, 2311 incident breast cancers occurred. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression for breast cancer overall and by estrogen receptor (ER) status. For heavy use (≥15 years of use for ≥7 times/year) of hair relaxers relative to never/light use (<4 years, no more than 1-2 times/year), the multivariable HR for breast cancer overall was 1.13 (95%CI: 0.96-1.33). Duration, frequency, age at first use and number of scalp burns were not associated with overall breast cancer risk. For heavy use of hair relaxers containing lye, the corresponding HR for ER+ breast cancer was 1.32 (95% CI: 0.97, 1.80); there was no association for non-lye products. There was no association of conditioner use and breast cancer. Results of this study were largely null, but there was some evidence that heavy use of lye-containing hair relaxers may be associated with increased risk of ER+ breast cancer. Consistent results from several studies are needed before it can be concluded that use of certain hair relaxers impacts breast cancer development.

Personal care product use among diverse women in California: Taking Stock Study

BACKGROUND

Personal care product use may contribute to elevated body burdens of consumer product chemicals among women of color; however, racial/ethnic differences in product use has been understudied. Community-engaged research can support the recruitment of diverse participants.

OBJECTIVE

To document personal care product use among a diverse group of women (aged 18-34 years) living in California.

METHODS

Through a community-academic partnership, we surveyed 357 women in California about product use information for 54 cosmetic, hair, menstrual/intimate care, and leave-on and rinse-off personal care products. We compared type and frequency of product use among Black, Hispanic/Latinx, Asian, and White women. We also summarized use of scented products and reasons women select products.

RESULTS

Women reported using a median of 8 products daily, with some women reporting up to 30 products daily. Hispanic/Latinx and Asian women used more cosmetics, and Black women used more hair and menstrual/intimate products than other women. Of the 54 products compared, there were significant differences in use by race/ethnicity for 28 products, with the largest number of significant differences between Black and White women.

SIGNIFICANCE

There is growing information on chemical exposures from personal care products and consequent adverse health effects, with implications for health disparities. Yet, there remains limited information on the range and types of products used by diverse racial/ethnic communities. This study helps close an important gap on product use inventories that can enable more informed public health interventions to limit exposures from personal care products.

Exposure to prenatal phthalate mixtures and neurodevelopment in the Conditions Affecting Neurocognitive Development and Learning in Early childhood (CANDLE) study

BACKGROUND

Findings from epidemiological studies of prenatal phthalate exposure and child cognitive development are inconsistent. Methods for evaluating mixtures of phthalates, such as weighted quantile sum (WQS) regression, have rarely been applied. We developed a new extension of the WQS method to improve specificity of full-sample analyses and applied it to estimate associations between prenatal phthalate mixtures and cognitive and language outcomes in a diverse pregnancy cohort.

METHODS

We measured 22 phthalate metabolites in third trimester urine from mother-child dyads who completed early childhood visits in the Conditions Affecting Neurodevelopment and Learning in Early childhood (CANDLE) study. Language and cognitive ability were assessed using the Bayley Scales of Infant Development (age 3) and the Stanford Binet-5 (age 4-6), respectively. We used multivariable WQS regression to identify phthalate mixtures that were negatively and positively associated with language score and full-scale IQ, in separate models, adjusted for maternal IQ, race, marital status, smoking, BMI, socioeconomic status (SES), child age, sex, and breastfeeding. We evaluated effect modification by sex and SES. If full sample 95% WQS confidence intervals (which are known to be anti-conservative) excluded the null, we calculated a p-value using a permutation test (ppermutation). The performance of this new approach to WQS regression was evaluated in simulated data. We compared the power and type I error rate of WQS regression conducted within datasets split into training and validation samples (WQSSplit) and in the full sample (WQSNosplit) to WQS regression with a permutation test (WQSpermutation). Individual metabolite associations were explored in secondary analyses.

RESULTS

The analytic sample (N = 1015) was 62.1% Black/31.5% White, and the majority of mothers had a high school education or less (56.7%) at enrollment. Associations between phthalate mixtures and primary outcomes (language score and full-scale IQ) in the full sample were null. Individual metabolites were not associated with IQ, and only one metabolite (mono-benzyl phthalate, MBzP) was associated with Bayley language score (β = -0.68, 95% CI: -1.37, 0.00). In analyses stratified by sex or SES, mixtures were positively and negatively associated with outcomes, but the precision of full-sample WQS regression results were not supported by permutation tests, with one exception. In the lowest SES category, a phthalate mixture dominated by mono-methyl phthalate (MMP) and mono-carboxy-isooctyl phthalate (MCOP) was associated with higher language scores (βlow SES = 2.41, full-sample 95%CI: 0.58, 4.24; ppermutation = 0.04). Performance testing in simulated data showed that WQSpermutation had improved power over WQSSplit (90% versus 56%) and a lower type I error rate than WQSNosplit (7% versus 47%).

CONCLUSIONS

In the largest study of these relationships to date, we observed predominantly null associations between mixtures of prenatal phthalates and both language and IQ. Our novel extension of WQS regression improved sensitivity to detect true associations by obviating the need to split the data into training and test sets and should be considered for future analyses of exposure mixtures.

Adolescent use of hair dyes, straighteners and perms in relation to breast cancer risk

Hair products can contain hormonally active and carcinogenic compounds. Adolescence may be a period of enhanced susceptibility of the breast tissue to exposure to chemicals. We therefore evaluated associations between adolescent hair product use and breast cancer risk. Sister Study participants (ages 35-74 years) who had completed enrollment questionnaires (2003-2009) on use of hair dyes, straighteners/relaxers and perms at ages 10 to 13 years (N = 47 522) were included. Cox proportional hazards regression was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for associations between hair products and incident breast cancer (invasive cancer or ductal carcinoma in situ), with consideration of heterogeneity by menopausal status and race/ethnicity. Over an average of 10 years of follow-up, 3380 cases were diagnosed. Frequent use of straighteners and perms was associated with a higher risk of premenopausal (HR = 2.11, 95% CI: 1.26-3.55 and HR = 1.55, 95% CI: 0.96-2.53, respectively) but not postmenopausal breast cancer (HR = 0.99, 95% CI: 0.76-1.30 and HR = 1.09, 95% CI: 0.89-1.35, respectively). Permanent hair dye use during adolescence was uncommon (<3%) and not associated with breast cancer overall (HR = 0.97, 95% CI: 0.78-1.20), though any permanent dye use was associated with a higher risk among black women (HR = 1.77, 95% CI: 1.01-3.11). Although frequency of use of perms (37% non-Hispanic white vs 9% black) and straighteners (3% non-Hispanic white vs 75% black) varied by race/ethnicity, associations with breast cancer did not. Use of hair products, specifically perms and straighteners, during adolescence may be associated with a higher risk of premenopausal breast cancer.

Association between gestational phthalate exposure and newborn head circumference; impacts by race and sex

Observational and experimental studies report associations between gestational phthalate exposure and fetal development, yet few data exist to characterize phthalate effects on head circumference (HC) or to estimate the impact of race or sex. To address this data gap, we enrolled 152 African American and 158 white mothers with uncomplicated singleton pregnancies from the Charleston, South Carolina (USA) metropolitan area in a prospective birth cohort. Study participants provided up to two urine specimens during mid and late gestation, completed a study questionnaire, and allowed access to hospital birth records. We measured eight phthalate monoester metabolites using liquid chromatography with tandem mass spectrometry, and calculated molar sums of phthalate parent diesters. After specific gravity correction, we tested for associations between phthalates and neonatal HC (cm) and cephalization index (cm/g) using multiple informant linear regression with inverse probability weighting to account for selection bias between repeated urine sampling, adjusted for maternal race, age, body mass index, education, and smoking. We explored interactions by maternal race and infant sex. A doubling of urinary monoethyl phthalate (MEP) concentration was associated with a -0.49% (95%CI: -0.95%, -0.02%) smaller head circumference, although seven other phthalate metabolites were null. There were no statistically significant associations with cephalization index. HC was larger for whites than African American newborns (p < 0.0001) but similar for males and females (p = 0.16). We detected interactions for maternal race with urinary monobutyl phthalate (MBP; p = 0.03), monobenzyl phthalate (MBzP; p = 0.01), monoethylhexyl phthalate (MEHP; p = 0.05), monomethyl phthalate (MMP; p = 0.02), and the sum of dibutyl phthalate metabolites (∑DBP; p = 0.05), in which reduced HC circumference associations were stronger among whites than African Americans, and interactions for sex with MBP (p = 0.08) and MiBP (p = 0.03), in which associations were stronger for females than males. Our results suggest that gestational phthalate exposure is associated with smaller neonatal HC and that white mothers and female newborns have greater susceptibility.

Low-Level Cadmium Exposure and Atherosclerosis

PURPOSE OF REVIEW

Cadmium has been recognized as a potential risk factor for cardiovascular disease (CVD). We present a review of cadmium toxicity, its effect on cellular activities, and a summary of reported association between environmental cadmium exposure and CVD. We also discuss the possible therapeutic benefit of cadmium chelation.

RECENT FINDINGS

Experimental data suggest that cadmium affects several signaling pathways which may lead to endothelial dysfunction and vascular tissue damage, promoting atherosclerosis. This is further supported by epidemiological studies that have shown an association of even low-level cadmium exposure with an increased risk of clinical cardiovascular events. The Trial to Assess Chelation Therapy (TACT) provided inferential evidence for the cardiovascular benefit of treating toxic metal burden. However, at the present time, there is no direct evidence, but suggestive findings from clinical trials indicating that removal of cadmium from body stores may be associated with improved cardiovascular outcomes. An evolving body of evidence supports environmental cadmium exposure as a pro-atherosclerosis risk factor in CVD; however, the mechanisms for the proatherogenic effect of cadmium are still not completely understood. Further studies in translational toxicology are needed to fill the knowledge gaps regarding the molecular mechanisms of cadmium toxicity and the promotion of atherosclerosis.

Acculturation and endocrine disrupting chemical-associated personal care product use among US-based foreign-born Chinese women of reproductive age

BACKGROUND

Personal care products (PCPs) are an important source of endocrine disrupting chemicals (EDCs) linked to adverse reproductive health outcomes.

OBJECTIVE

We evaluated EDC-associated PCP use and acculturation among Asian women.

METHODS

Our study included 227 foreign-born Chinese women ages 18-45 seeking obstetrics-gynecology care at community health centers (Boston, MA). Acculturation was measured by English-language use, length of US residence, and age at US entry. Self-reported use of PCPs (crème rinse/conditioner, shampoo, perfume/cologne, bar soap/body wash, liquid hand soap, moisturizer/lotion, colored cosmetics, sunscreen, and nail polish) in the last 48 h was collected. Latent class analysis was used to identify usage patterns. We also conducted multivariable logistic to determine the cross-sectional associations of acculturation measures and the use of individual PCP types.

RESULTS

Those who used more PCP types, overall and by each type, tended to be more acculturated. Women who could speak English had 2.77 (95% CI: 1.10-7.76) times the odds of being high PCP users compared to their non-English speaking counterparts. English-language use was associated with higher odds of using perfume/cologne and nail polish.

SIGNIFICANCE

Our findings give insight about EDC-associated PCP use based on acculturation status, which can contribute to changes in immigrant health and health disparities.

Maternal Food and Beverage Consumption Behaviors and Discrepant Phthalate Exposure by Race

Background: Differential exposure to endocrine-disrupting chemicals, including phthalate diesters, may contribute to persistent racial/ethnic disparities in women’s reproductive health outcomes. We sought to characterize sources of gestational exposure to these agents that may differ according to maternal race. Methods: We enrolled pregnant Black (n = 198), including African American, and White (n = 197) women during the second trimester, and measured eight phthalate monoester metabolites in urine. We assessed confounder-adjusted associations between multiple food and beverage consumption habits, summarized using a principal component analysis, as predictors of maternal urinary phthalate metabolite levels, stratified by race. Results: Whites reported significantly greater unprocessed food consumption (42.5% vs. 32.0%; p < 0.001) and storage of food in clear unbreakable plastic containers (66.5% vs. 49.3%; p < 0.001) than Blacks, while Blacks consumed more canned fruits and vegetables (23.5% vs. 12.2%; p < 0.001) than Whites. Using plastics for food storage, microwaving in plastic containers, and using hard plastic water bottles was associated with urinary phthalate concentrations, especially DEHP metabolites (e.g., mean difference = 5.13%; 95% CI: 3.05, 7.25). These associations were driven primarily by Black pregnant women. Conclusions: Targeted interventions to reduce maternal exposure to phthalates need to be designed with specific attention to differences in food and beverage consumption behaviors among Black and White women.

Effects and Mechanisms of Phthalates' Action on Reproductive Processes and Reproductive Health: A Literature Review

The production of plastic products, which requires phthalate plasticizers, has resulted in the problems for human health, especially that of reproductive health. Phthalate exposure can induce reproductive disorders at various regulatory levels. The aim of this review was to compile the evidence concerning the association between phthalates and reproductive diseases, phthalates-induced reproductive disorders, and their possible endocrine and intracellular mechanisms. Phthalates may induce alterations in puberty, the development of testicular dysgenesis syndrome, cancer, and fertility disorders in both males and females. At the hormonal level, phthalates can modify the release of hypothalamic, pituitary, and peripheral hormones. At the intracellular level, phthalates can interfere with nuclear receptors, membrane receptors, intracellular signaling pathways, and modulate gene expression associated with reproduction. To understand and to treat the adverse effects of phthalates on human health, it is essential to expand the current knowledge concerning their mechanism of action in the organism.

Chemical/straightening and other hair product usage during childhood, adolescence, and adulthood among African-American women: potential implications for health

Few studies have characterized life course hair product usage beyond ever/never. We investigated hair product use from childhood to adulthood, usage patterns in adulthood, and socioeconomic status (SES) correlates among African-American (AA) women. Using self-reported data from 1555 AA women enrolled in the Study of Environment, Lifestyle, and Fibroids (2010-2018), we estimated the usage frequency of chemical relaxer/straightener (≥twice/year, once/year, and rarely/never) and leave-in/leave-on conditioner (≥once/week, 1-3 times/month, and rarely/never) during childhood, adolescence, and adulthood. Latent class analysis was used to identify patterns of adulthood usage of multiple hair products. SES was compared across latent classes. With a mean age of 33 ± 3.4 years, most women reported ever using chemical relaxers/straighteners (89%), and use ≥twice/year increased from childhood (9%) to adolescence (73%) but decreased in adulthood (29%). Leave-in/leave-on conditioner use followed the same pattern. Each of three identified latent classes reported frequent styling product use and infrequent relaxer/straightener use. Class One was unlikely to use any other products, Class Two moderately used shampoo and conditioner, and Class Three frequently used multiple product types (e.g., moisturizers and conditioners). Participants in the latter two classes reported higher SES. Ever/never characterization may miss important and distinctive patterns of hair product use, which may vary by SES.

Joint Impact of Synthetic Chemical and Non-chemical Stressors on Children's Health

PURPOSE OF REVIEW

Pregnant women are exposed to numerous synthetic chemicals (e.g., pesticides, phthalates, polychlorinated biphenyls) in their daily lives as well as a range of non-chemical stressors, including poverty, depression, discrimination, and stressful life events. Although many studies have examined individual exposures to chemical and non-chemical stressors in relation to child health outcomes, very few studies have considered these exposures together. Here, we review the recent epidemiologic literature on the joint impact of chemical and non-chemical stressors on child outcomes.

RECENT FINDINGS

Considerable co-exposure to chemical and non-chemical stressors occurs in vulnerable populations. Non-chemical stressors may modify the impact of chemical exposures on children's health, typically exacerbating their negative impact, but associations differ considerably by the chemicals and populations of interest. Additional research is urgently needed to better understand the cumulative risks of multiple stressors on children's health and the underlying physiological mechanisms.

Racial disparity in maternal phthalates exposure; Association with racial disparity in fetal growth and birth outcomes

Experimental and observational data implicate phthalates as developmental toxicants. However, few data are available to assess the maternal risks of gestational exposure by race and infant sex. To begin to address this data gap, we characterized associations between maternal urinary phthalate metabolites and birth outcomes among African American and white mothers from a southeastern U.S. population. We enrolled pregnant African American (n = 152) and white (n = 158) women with singleton live births between 18 and 22 weeks gestation. We measured phthalate metabolites (mono-n-butyl phthalate (MBP), monoisobutyl phthalate (MiBP), monobenzyl phthalate (MBzP), mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), monoethyl phthalate (MEP), monomethyl phthalate (MMP), and the sums of DEHP (ΣDEHP) and DBP (ΣDBP) metabolites) in up to two gestational urine specimens from mothers, and evaluated confounder-adjusted associations per natural log unit greater concentration with birth weight for gestational age z-score, small for gestational age (SGA; <10th %tile), preterm birth (PTB; <37 weeks gestation), and low birth weight (LBW; <2500 g). We also tested for interactions by maternal race and infant sex. We found that lower z-scores were associated with greater MiBP (β = -0.28; 95% CI: -0.54, -0.02) and MMP (β = -0.30; 95% CI: -0.52, -0.09) concentrations, while MEP interacted with race (p = 0.04), indicating an association among whites (β = -0.14; 95% CI: -0.28, 0.001) but not among African Americans (β = 0.05; 95% CI = -0.09, 0.19). Greater MiBP (OR = 2.82; 95% CI: 1.21, 6.56) and MEOHP (OR = 2.80; 95% CI: 1.05, 7.42) were associated with an overall higher SGA risk, greater MEHP was associated with higher SGA risk (p = 0.10) in whites (OR = 3.26 95% CI: 0.64, 16.56) but not in African Americans (OR = 0.71 95% CI: 0.07, 7.17), and the associations for MiBP (p = 0.02) and ΣDBP (p = 0.02) varied by infant sex. We detected interactions for PTB in which African Americans were at higher risk than whites for greater MiBP (p = 0.08) and MEP (p = 0.02) although lower risk for greater MEHP (p = 0.09). Greater MEP was associated with an overall higher LBW risk (OR = 1.33; 95% CI: 0.95, 1.86), and males were at higher risk than females with greater MBP (p = 0.002), MiBP (p = 0.02), MBzP (p = 0.01), MEP (p = 0.002), MMP (p = 0.09), and ΣDBP (p = 0.01) concentrations. Overall, our results suggest that gestational phthalate exposure is associated with adverse maternal birth outcomes, and that the effects vary by maternal race and infant sex.

In utero effects of maternal phthalate exposure on male genital development

BACKGROUND

Phthalates are used extensively in commercial and personal care products and maternal exposure is ubiquitous. Phthalates are anti-androgenic, but the potential effects of phthalates on male penile development have not been assessed in utero.

OBJECTIVE

The study aims to investigate the association between early pregnancy phthalate exposure and fetal penile development, overall and by race.

METHODS

Prospective cohort study of women with singleton pregnancies presenting for prenatal ultrasound between 18 and 22 weeks' gestation. Maternal urine samples were assayed for eight phthalate monoester metabolites. We used maternal phthalate levels at 18 to 22 weeks' gestation as predictors of fetal size using multiple linear regression models, adjusted for fetal gestational age, maternal age, race, smoking, and education. We incorporated a phthalate by race interaction into a second set of regression models.

RESULTS

We detected statistically significant race interactions for continuous phthalates with penile width. Race interactions were also suggested for penile length and volume using tertiles of phthalates with point estimates generally positive for whites and negative for African Americans.

CONCLUSION

Penile development is significantly influenced by race, and the impact of maternal phthalates on penile measurements also varies by race. Maternal phthalate exposure can adversely affect in utero penile growth and development, especially among African Americans.

Phthalates exposure and uterine fibroid burden among women undergoing surgical treatment for fibroids: a preliminary study

OBJECTIVES

To examine the association between phthalate exposure and two measures of uterine fibroid burden: diameter of largest fibroid and uterine volume.

DESIGN

Pilot, cross-sectional study.

SETTING

Academic medical center.

PATIENT(S)

Fifty-seven premenopausal women undergoing either hysterectomy or myomectomy for fibroids.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The diameter of the largest fibroid and uterine dimensions were abstracted from medical records. Spot urine samples were analyzed for 14 phthalate biomarkers using mass spectrometry. We estimated associations between fibroid outcomes and individual phthalate metabolites, sum of di(2-ethylhexyl) phthalate metabolites (∑DEHP), and a weighted sum of anti-androgenic phthalate metabolites (∑AA Phthalates) using linear regression, adjusting for age, race/ethnicity, and body mass index. Fibroid outcomes were also examined dichotomously (divided at the median) using logistic regression.

RESULTS

Most women were of black ethnicity, overweight or obese, and college educated. In multivariable models, higher levels of mono-hydroxyisobutyl phthalate, monocarboxyoctyl phthalate, monocarboxynonyl phthalate, mono(2-ethylhexyl) phthalate, mono(2-ethyl-5-hydroxyhexyl phthalate) (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), ∑DEHP, and ∑AA Phthalates were positively associated with uterine volume. Associations were most pronounced for individual DEHP metabolites (MEHHP, MEOHP, MECPP), ∑DEHP, and ∑AA Phthalates. For example, a doubling in ∑DEHP and ∑AA Phthalates was associated with 33.2% (95% confidence interval 6.6-66.5) and 26.8% (95% confidence interval 2.2-57.4) increase in uterine volume, respectively. There were few associations between phthalate biomarkers and fibroid size.

CONCLUSIONS

Exposure to some phthalate biomarkers was positively associated with uterine volume, which further supports the hypothesis that phthalate exposures may be associated with fibroid outcomes. Additional studies are needed to confirm these relationships.