Urinary phthalate metabolite concentrations and hot flashes in women from an urban convenience sample of midlife women

Abstract

Context: Phthalate exposure is associated with altered reproductive function, but little is known about associations of phthalate exposure with risk of hot flashes.

Objective: To investigate associations of urinary phthalate metabolite levels with four hot flash outcomes in midlife women.

Design: A cross-sectional study of the first year of a prospective cohort of midlife women, the Midlife Women's Health Study (2006-2015), a convenience sample from an urban setting.

Participants: 728 multi-racial/ethnic pre- and perimenopausal women aged 45-54 years.

Outcome measures: Women completed questionnaires about hot flash experience and provided 1-4 urine samples over four consecutive weeks that were pooled for analysis. Phthalate metabolites were assessed individually and as molar sums representative of common compounds (all phthalates: ƩPhthalates; DEHP: ƩDEHP), exposure sources (plastics: ƩPlastic; personal care products: ƩPCP), and modes of action (anti-androgenic: ƩAA). Covariate-adjusted logistic regression models were used to assess associations of continuous natural log-transformed phthalate metabolite concentrations with hot flash outcomes. Analyses were conducted to explore whether associations differed by menopause status, body mass index (BMI), race/ethnicity, and depressive symptoms.

Results: Overall, 45% of women reported a history of hot flashes. Compared to women who never experienced hot flashes, every two-fold increase in ƩPlastic was associated with 18% (OR: 1.18; 95%CI: 0.98, 1.43) and 38% (OR: 1.38; 95%CI: 1.11, 1.70) higher odds of experiencing hot flashes in the past 30 days and experiencing daily/weekly hot flashes, respectively. Some associations of phthalates with certain hot flash outcomes differed by menopause status, BMI, race/ethnicity, and depressive symptoms.

Conclusions: This study suggests that phthalates are associated with hot flash experience and may impact hot flash risk in women who are susceptible to experiencing hot flashes.

Keywords: Hot flashes; Menopause; Phthalates; Women.