title: Detecting Associations between Early-Life DDT Exposures and Childhood Growth Patterns: A Novel Statistical Approach.
abstract: It has been hypothesized that environmental exposures at key development periods such as in utero play a role in childhood growth and obesity. To investigate whether in utero exposure to endocrine-disrupting chemicals, dichlorodiphenyltrichloroethane (DDT) and its metabolite, dichlorodiphenyldichloroethane (DDE), is associated with childhood physical growth, we took a novel statistical approach to analyze data from the CHAMACOS cohort study. To model heterogeneity in the growth patterns, we used a finite mixture model in combination with a data transformation to characterize body mass index (BMI) with four groups and estimated the association between exposure and group membership. In boys, higher maternal concentrations of DDT and DDE during pregnancy are associated with a BMI growth pattern that is stable until about age five followed by increased growth through age nine. In contrast, higher maternal DDT exposure during pregnancy is associated with a flat, relatively stable growth pattern in girls. This study suggests that in utero exposure to DDT and DDE may be associated with childhood BMI growth patterns, not just BMI level, and both the magnitude of exposure and sex may impact the relationship.
authors.affiliation: Department of Mathematics and Statistics, Williams College, Williamstown, MA, United States of America.
authors.forename: Brianna
authors.initials: B
authors.lastname: Heggeseth
authors.affiliation: Center for Environmental Research and Children's Health, School of Public Health, University of California, Berkeley, California, United States of America.
authors.forename: Kim
authors.initials: K
authors.lastname: Harley
authors.affiliation: Center for Environmental Research and Children's Health, School of Public Health, University of California, Berkeley, California, United States of America.
authors.forename: Marcella
authors.initials: M
authors.lastname: Warner
authors.affiliation: Division of Biostatistics, School of Public Health, University of California, Berkeley, California, United States of America.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Jewell
authors.affiliation: Center for Environmental Research and Children's Health, School of Public Health, University of California, Berkeley, California, United States of America.
authors.forename: Brenda
authors.initials: B
authors.lastname: Eskenazi
mesh_terms: D015992:Body Mass Index; D015331:Cohort Studies; D003634:DDT / Q000097:blood / Q000633:toxicity*; D003633:Dichlorodiphenyl Dichloroethylene / Q000097:blood / Q000633:toxicity*; D052244:Endocrine Disruptors / Q000633:toxicity*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects; D009765:Obesity; D063766:Pediatric Obesity / Q000139:chemically induced*; D011078:Polychlorinated Biphenyls; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000139:chemically induced*; D012737:Sex Factors
chemical_list: D052244:Endocrine Disruptors; D003633:Dichlorodiphenyl Dichloroethylene; D003634:DDT; D011078:Polychlorinated Biphenyls