The Association of National Air Toxics Assessment Exposures and the Risk of Childhood Autism Spectrum Disorder: A Case Control Study
EVELYN TALBOTT, Lynne Marshall, Judith Rager, Vincent Arena, Ravi Sharma, University of Pittsburgh
Abstract Number: 599
Working Group: Health Related Aerosols
Abstract
Background: Autism spectrum disorders (ASD) constitute a major public health problem, affecting one in every 68 children. There is little understanding of the cause of ASD despite its serious social impact. Air pollution contains many toxicants known to have adverse effects on the developing fetus.
Methods: We conducted a population-based case control study in six southwestern PA counties estimating the association between ASD and USEPA census tract modeled NATA levels for 30 neurotoxicants. Cases were recruited from local ASD treatment centers. There were two different control groups: 1) Interviewed controls with complete residential histories from pre-pregnancy through age two recruited through mailings using the Pennsylvania Department of Health birth registry (2005-2009). 2) 5,007 non-interviewed controls from a random sample of the birth records using residence at birth. Logistic regression analysis was conducted using quartiles of exposure, adjusting for age of mother, smoking, race, and education.
Results: There were a total of 217 cases. For the first group of 224 controls, median levels of chromium, styrene, cyanide, and polycyclic aromatic hydrocarbons were higher in cases compared to controls (p<.05). Women in the highest quartile of exposure to styrene had an odds ratio of 1.78 (95% CI: 1.035-3.068) of having a child with ASD compared to the lowest quartile, after adjustment for covariates. In the second control group, each increase of interquartile range exposure to cyanide resulted in a 16% higher odds (95%CI; 1.04-3.46) of ASD in the adjusted logistic model. Additionally, women with the highest quartile of exposure to chromium had 1.65 (95%CI; 1.10-2.47) times the odds of having a child with ASD compared to the women in the lowest quartile of chromium exposure.
Conclusions: Chromium, cyanide and styrene exhibited elevated odds ratios using two different control groups. These findings need to be verified with exposure assessment at the individual level.