Determinants of urinary phthalate biomarker concentrations in pre- and perimenopausal women with consideration of race

Background/Objectives: Phthalates are endocrine disruptors in consumer plastics and personal care products. Our objectives were to identify determinants of phthalate biomarkers in women during the hormonally-sensitive midlife period, and to consider differences between non-Hispanic White and Black women. Methods: We used information from the Midlife Women's Health Study of pre- and pen-menopausal women from Baltimore, Maryland (enrolled 2006-2015). We collected sociodemographic/health information via baseline questionnaires or during clinic visits and measured nine phthalate metabolites in pools of 2-4 urines collected across one menstrual cycle. We calculated molar sums of metabolites to estimate exposure to di(2-ethylhexyl) phthalate (Sigma DEHP), personal care product phthalates (Sigma PCPs), and phthalates in plastics (Sigma Plastics). Accounting for meaningful predictors from bivariable analyses, our multivariable linear regression models evaluated determinants of phthalate biomarkers in all women (n = 689), non-Hispanic White women only (n = 467), or non-Hispanic Black women only (n = 195). Results: In multivariable analyses of all women, those who were perimenopausal, widowed/divorced, non-Hispanic Black, with higher family income, with lower BMI, or who reported more frequent nausea had higher monoethyl phthalate (MEP) and Sigma PCP. Non-Hispanic White women who were perimenopausal had lower mono-(3-carboxypropyl) phthalate (MCPP) and monobutyl phthalate (MBP), those who consume alcohol had higher mono-isobutyl phthalate (MiBP), and those with higher BMI had lower MEP and higher MCPP. Alternatively, widowed/divorced Black women had higher Sigma DEHP, monobenzyl phthalate (MBzP), and Sigma Plastics, whereas Black women with higher income had higher MEP and Sigma PCP. Black women who described themselves as having "as much" physical activity as others or who reported a skin condition had lower MBzP and MCPP, respectively. Conclusion: We identified important determinants of phthalate biomarkers in midlife women and observed some differences by race. Future studies could consider reasons for these differences when developing interventions to reduce phthalate disparities and related health effects.