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Background: Certain types of hair products are more commonly used by Black women. Studies show hair products contain several endocrine-disrupting chemicals that are associated with adverse health outcomes. As chemical mixtures of endocrine disruptors, hair products may be hormonally active, but this remains unclear. Objective: To assess the hormonal activity of commonly used Black hair products. Methods: We identified six commonly used hair products (used by >10% of the population) from the Greater New York Hair Products Study. We used reporter gene assays (RGAs) incorporating natural steroid receptors to evaluate estrogenic, androgenic, progestogenic, and glucocorticoid hormonal bioactivity employing an extraction method using bond elution prior to RGA assessment at dilutions from 50 to 500. Results: All products displayed hormonal activity, varying in the amount and effect. Three samples showed estrogen agonist properties at levels from 12.5 to 20 ng/g estradiol equivalent concentrations All but one sample showed androgen antagonist properties at levels from 20 to 25 ng/g androgen equivalent concentrations. Four samples showed antagonistic and agonistic properties to progesterone and glucocorticoid. Significance: Hair products commonly used by Black women showed hormonal activity. Given their frequent use, exposure to hormonally active products could have implications for health outcomes and contribute to reproductive and metabolic health disparities.

Background Prenatal endocrine disrupting chemical (EDC) exposure has been associated with increased risk of preterm birth. Non-Hispanic Black women have higher incidence of preterm birth compared to other racial/ethnic groups and may be disproportionately exposed to EDCs through EDC-containing hair products. However, research on the use of EDC-associated hair products during pregnancy and risk of preterm birth is lacking. Therefore, the objective of this pilot study was to estimate associations of prenatal hair product use with gestational age at delivery in a Boston, Massachusetts area pregnancy cohort. Methods The study population consisted of a subset of participants enrolled in the Environmental Reproductive and Glucose Outcomes (ERGO) Study between 2018 and 2020. We collected self-reported data on demographics and hair product use using a previously validated questionnaire at four prenatal visits (median: 12, 19, 26, 36 weeks’ gestation) and abstracted gestational age at delivery from medical records. We compared gestational age and hair product use by race/ethnicity and used linear regression to estimate covariate-adjusted associations of product use and frequency of use at each study visit with gestational age at delivery. Primary models were adjusted for maternal age at enrollment and delivery method. Results Of the 154 study participants, 7% delivered preterm. Non-Hispanic Black participants had lower mean gestational age at delivery compared to non-Hispanic White participants (38.2 vs. 39.2 weeks) and were more likely to report ever and more frequent use of hair products. In regression models, participants reporting daily use of hair oils at visit 4 had lower mean gestational age at delivery compared to non-users (β: -8.3 days; 95% confidence interval: -14.9, -1.6). We did not find evidence of associations at earlier visits or with other products. Conclusions Frequent use of hair oils during late pregnancy may be associated with shorter gestational duration. As hair oils are more commonly used by non-Hispanic Black women and represent potentially modifiable EDC exposure sources, this may have important implications for the known racial disparity in preterm birth.

Background Exposure to ionizing radiation has been associated with insulin resistance and type 2 diabetes. In light of recent work showing an association between ambient particulate matter (PM) gross β-activity and gestational diabetes mellitus (GDM) among pregnant women, we examined pregnancy glucose levels in relation to PM gross β-activity to better understand this pathway. Methods Our study included 103 participants receiving prenatal care at Beth Israel Deaconess Medical Center in Boston, MA. PM gross β-activity was obtained from US Environmental Protection Agency’s RadNet program monitors, and blood glucose levels were obtained from the non-fasting glucose challenge test performed clinically as the first step of the 2-step GDM screening test. For each exposure window we examined (i.e., moving average same-day, one-week, first-trimester, and second-trimester PM gross β-activity), we fitted generalized additive models and adjusted for clinical characteristics, socio-demographic factors, temporal variables, and PM with an aerodynamic diameter ≤ 2.5 μm (PM2.5). Subgroup analyses by maternal age and by body mass index were also conducted. Results An interquartile range increase in average PM gross β-activity during the second trimester of pregnancy was associated with an increase of 17.5 (95% CI: 0.8, 34.3) mg/dL in glucose concentration. Associations were stronger among younger and overweight/obese participants. Our findings also suggest that the highest compared to the lowest quartile of one-week exposure was associated with 17.0 (95% CI: − 4.0, 38.0) mg/dL higher glucose levels. No associations of glucose were observed with PM gross β-activity during same-day and first-trimester exposure windows. PM2.5 was not associated with glucose levels during any exposure window in our data. Conclusions Exposure to higher levels of ambient PM gross β-activity was associated with higher blood glucose levels in pregnant patients, with implications for how this novel environmental factor could impact pregnancy health.