Because little is known about non-genetic causes�of�autism spectrum disorders (ASD), this proposal seeks a novel approach to advance our knowledge�of�the complex etiology�of�autism due to environmental chemical exposures from the use�of�common consumer products. Phthalates are selected as a chemical class�of�interest because they are ubiquitous in personal care products (e.g., cosmetics, fragrances, shampoos) and indoor residential environments (e.g., polyvinyl chloride (PVC) flooring and plastics, children's toys, vinyl tiles, shower curtains), have been shown to influence sex steroids critical n early brain development, and have neuro- developmental toxicity in infants and children. A recent epidemiologic study also found that having PVC flooring material (a source�of�airborne phthalates) in a parent's or child's room was associated with an increased risk�of�ASD. The overall goal�of�this project is to determine whether exposure to phthalates during pregnancy is associated with an increased risk�of�ASD. To estimate prenatal exposure to phthalates, this study will leverage existing resources from a unique longitudinal study initiated under the NIEHS-funded UC Davis Center�for�Children's Environmental Health known as "MARBLES" (Markers�of�Autism Risk in Babies - Learning Early Signs). MARBLES is a prospective investigation, enrolling pregnant women who already have a child with ASD and are therefore at high risk�for�delivering another child with autism, designed to identify causes and early markers�of�autism. From this study, we have available multiple urine samples collected from the mother throughout pregnancy, a key feature�for�improving the exposure estimates�for�each infant and mother due to the fact that phthalates are metabolized and excreted quickly, with elimination half-lives on the order�of�hours. Moreover, two hundred fifteen�of�the children from this pregnancy cohort will have been assessed�for�autism at the age�of�36 months during the time�of�this R21, enriching the value�of�these prenatal biological samples. Close to one in five�of�the firt 147 children to reach 36 months has been confirmed with a diagnosis�of�ASD. Other developmental diagnoses, including adaptive function and cognitive development, are also available�for�these children. Therefore, multiple gestational urine samples collected from mothers and confirmed diagnoses�of�autism in MARBLES are invaluable resources that will enable rigorous analyses�of�the association between prenatal exposure to phthalates and the risk�for�ASD or other developmental concerns. Up to four urine samples were collected each trimester�for�each woman. To reduce analytical costs while maintaining some information about variability, we will analyze the first sample collected each trimester as an individual sample and pool all remaining samples�for�that trimester. To assess variability�of�maternal exposures during pregnancy, longitudinal individual urine samples collected approximately one week apart from 9 mothers will be analyzed�for�phthalate metabolite levels. This study will markedly advance understanding�of�the role�of�a class�of�endocrine disrupting compounds common in consumer products on ASD.
Interagency Autism Coordinating Committee (IACC)
Autism Research Database (AFD)
