Link to the University of Pittsburgh Homepage
Link to the University Library System Homepage Link to the Contact Us Form

Environmental risk factors for autism spectrum disorder (ASD)

Marshall, Lynne (2015) Environmental risk factors for autism spectrum disorder (ASD). Doctoral Dissertation, University of Pittsburgh. (Unpublished)

Submitted Version

Download (1MB)


Background: Autism Spectrum Disorder (ASD) is a significant public health concern. The prevalence rate of this heterogeneous group of neurological conditions has more than doubled in the US during the last twenty years. The amount and cost of care needed to provide support and services for families impacted by ASD are increasing as well. Current research suggests that the etiology of ASD is not wholly genetic. The objective of this research is to investigate environmental contributors to the disease. Parental, prenatal, and obstetric factors and exposure to air pollutants during the prenatal period were examined for potential associations with ASD status.
Methods: Risk factors were extracted from the birth certificates of singleton cases (n=198) and controls (n=4,801) from the Case-Control Study of Personal and Environmental Risk Factors for Childhood Autism in Southwestern Pennsylvania. Cases and controls were born between 2005 and 2009. The 2005 National Air Toxics Assessment (NATA) and the Toxic Release Inventory (TRI) for 2004 – 2009 were used to estimate air pollutant exposure during pregnancy. Logistic regression models estimated the odds of being an ASD case in all investigations.
Results: Multivariable logistic regression modelling showed that increased maternal age, greater maternal education, gestational hypertension, cesarean delivery, and maternal infection were independent risk factors for ASD. In the analysis comparing higher quartiles of NATA exposure estimates of metal compounds to the lowest quartile of metal exposure at mother’s residence at the time of her child’s birth, arsenic, chromium, and lead were significantly associated with being an ASD case. However, an analysis of proximity to chromium emitting industrial sites, as reported in the TRI, uncovered no elevated or statistically significant association with ASD status.
Conclusions: Maternal and birth characteristics as well as exposure to metal compounds during the prenatal period were shown to have an association with ASD in this case-control study. This research adds to a growing body of literature suggesting that environmental risk factors contribute to the ASD burden. However, improved exposure assessment methods and a prospective study design would aid in establishing a causal association.


Social Networking:
Share |


Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Marshall, Lynnelpm18@pitt.eduLPM18
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairTalbott, Evelyn O.eot1@pitt.eduEOT1
Committee MemberSharma, Ravirks1946@pitt.eduRKS1946
Committee MemberArena, Vincent C.arena@pitt.eduARENA
Committee MemberHaggerty, Catherinehaggerty@pitt.eduHAGGERTY
Committee MemberBrink, Luann
Date: 28 January 2015
Date Type: Publication
Defense Date: 10 December 2014
Approval Date: 28 January 2015
Submission Date: 23 November 2014
Access Restriction: 3 year -- Restrict access to University of Pittsburgh for a period of 3 years.
Number of Pages: 118
Institution: University of Pittsburgh
Schools and Programs: School of Public Health > Epidemiology
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: autism autism spectrum disorder ASD air pollution environmental risk factors
Date Deposited: 28 Jan 2015 16:47
Last Modified: 01 Jan 2018 06:15


Monthly Views for the past 3 years

Plum Analytics

Actions (login required)

View Item View Item