Maternal Residential Proximity to Toxic Release Inventory Sites In Children with ASD and Other Developmental Disabilities

Background:  Researchers have hypothesized that hazardous air pollutant exposures during critical periods of prenatal neurodevelopment could alter normal development.

Objectives:  The objective of this study was to explore the hypothesis that a higher proportion of children with ASD and other developmental disabilities had maternal birth addresses within ¼ mile, ½ mile, and 1 mile buffer zones of Toxic Release Inventory (TRI) sites than expected.

Methods:  Children born in 1994 (n= 23,609) with ASD (n=99), speech language impairment (SLI, n=838), and/or attention deficit hyperactivity disorder (ADHD, n=47) were identified by the Utah Registry of Autism and Developmental Disabilities. Maternal residential addresses obtained from birth records were geocoded for cases and controls.   Environmental air pollutant data specific to TRI sites were obtained by year, chemical type, and annual poundage of emission.  The proportion of cases and controls occurring within buffer zones were compared.  Observed and expected values (O|E), odds ratios and 95% confidence intervals (OR 95% C.I.) and P values were calculated.

Results:  Higher than expected proportions of children from the birth cohort with ASD and other developmental disabilities were identified in the one mile buffer zones surrounding some TRI sites by chemical type and annual poundage of emission.

Conclusions:  Halogenated chemicals emerged as candidates that warrant further investigation for a possible role in the etiology of ASD and other developmental disabilities.  The role of potential confounding variables in this preliminary study needs further exploration.