Abstracts: ISEE 21st Annual Conference, Dublin, Ireland, August 25-29, 2009: Oral Presentations
Background and Objective:
Several studies have reported possible antagonistic effects of phthalates on the thyroid gland in vivo and thyroid tissue in vitro, suggesting that phthalate exposure may have neurodevelopmental consequences. We undertook an investigation of the neurobehavioral consequences of prenatal phthalate exposure in a prospective birth cohort.
The Mount Sinai Children's Environmental Health Study enrolled a multiethnic prenatal population of 404 singleton, primiparous women in New York City between 1998-2002. Maternal urine was collected in the third trimester, and children were reassessed for growth and neurodevelopment at approximately ages 4, 6 and 8 years. At their exam, mothers completed the parent-report form of the Behavioral Assessment System for Children (BASC) and the Behavior Rating Inventory of Executive Function (BRIEF). In total, 181 (45%) children returned for at least one visit (n = 343 visits). Prenatal urine was analyzed for phthalate metabolites, which were grouped by molecular weight into monoester metabolites of high- (>250 dalton) (HMW), and low- (<250 dalton) (LMW) molecular weight.
In multivariate adjusted generalized linear models, increased log-LMW phthalate metabolite concentrations were associated with poorer BASC scores on the Aggression (B = 1.24, 95% CI 0.15-2.34), Attention Problems (1.29, 0.16-2.41), Conduct Problems (2.40, 1.34-3.46), and Depression (1.18, 0.11-2.24) clinical scales; and Externalizing Problems (1.75, 0.61-2.88) and Behavioral Symptom Index (1.55, 0.39-2.71) composite scales. For the BRIEF, in multivariate adjusted models, increased log-LMW phthalate concentrations were associated with poorer scores on the Global Executive Composite index (1.23, 0.09-2.36), and the Emotional Control scale (1.33, 0.18-2.49).
These associations include domains that are typically affected in childhood Conduct Disorder, ADHD, and Depression clinical groups. Given the ubiquity of phthalates in the environment, the public health impact of even small adverse effects of phthalates on neurodevelopment could be significant. Replication of these findings is needed.