Associations of urinary phthalates and phenols with menarche among a multiethnic cohort of young girls

Abstract

Hormonally active environmental exposures may alter timing of puberty. We investigated urinary biomarkers of 9 phthalates and 13 phenols including 3 phytoestrogens in relation to menarche among girls enrolled at 6-8 years of age during 2004-2007 in the Breast Cancer and Environment Research Program. This multi-ethnic cohort study of 1239 girls at three US sites was followed through 2015. For urinary metabolites assayed in baseline samples, age at menarche was available on 1051 girls. Associations of biomarker quintiles with menarche were estimated from Cox proportional hazards models adjusted for race, ethnicity, and caregiver education (aHR, 95% confidence intervals [CI]). Urinary enterolactone was associated with later age at menarche (aHR 0.82 [0.66-1.03] for 5th vs 1st quintile, p-trend 0.028). Effects were stronger in girls with below-median body mass index (aHR 0.75 [0.59-0.95], 3rd vs 1st enterolactone tertile) compared to higher body mass (aHR 1.04 [0.82-1.33]). 2,5-Dichlorophenol was associated w...