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About the Authors:
Pam Factor-Litvak
* E-mail: [email protected]
Affiliation: Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, United States of America
Beverly Insel
Affiliation: Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, United States of America
Antonia M. Calafat
Affiliation: National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
Xinhua Liu
Affiliation: Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, New York, United States of America
Frederica Perera
Affiliation: Department of Environmental Health Sciences, Columbia Center for Children’s Environmental Health, Mailman School of Public Health, Columbia University, New York, New York, United States of America
Virginia A. Rauh
Affiliation: Heilbrunn Department of Population and Family Health, Mailman School of Public Health, Columbia University, New York, New York, United States of America
Robin M. Whyatt
Affiliation: Department of Environmental Health Sciences, Columbia Center for Children’s Environmental Health, Mailman School of Public Health, Columbia University, New York, New York, United States of America
Introduction
Phthalates are a class of high production chemicals widely used as plasticizers and additives in consumer and personal care products [1]. Many phthalates are endocrine disruptors which may operate through multiple mechanisms including perturbations in thyroid hormone and testosterone levels [2], [3]. Exposures to phthalates are ubiquitous [4], [5]. Urinary concentrations of phthalate metabolites are used as internal dosimeters because urinary enzymatic activity is negligible [6]; thus metabolite concentrations in urine reflect an individual’s internal exposure to phthalates, rather than phthalate contaminants introduced during sample collection and processing. Prior studies have shown moderate reproducibility (i.e. intraclass correlation coefficients ranging from approximately 0.20 to 0.77) for measurements of several phthalate metabolite concentrations in repeat spot urine samples [5], [7]–[9].
Limited epidemiologic studies have reported inverse associations between phthalate metabolites in maternal prenatal urine and child mental, motor and behavioral development [5], [10]. Previously, we reported that maternal prenatal urinary concentrations of mono-n-butyl phthalate (MnBP) and monoisobutyl phthalate (MiBP), the main metabolites of di-n-butyl phthalate (DnBP) and di-isobutyl phthalate (DiBP), respectively, were inversely associated with child age 3 year motor development and increased the risk of motor delay [5]. Among girls, MiBP was also inversely associated with mental development [5]. Experimental...