Changes in autism spectrum disorder prevalence in 4 areas of the United States
published online 04 January 2010.
Abstract
Background
We sought to describe autism spectrum disorder (ASD) population characteristics and changes in identified prevalence across 3 time periods.
Methods
Children with a potential ASD were identified through records abstraction at multiple sources with clinician review based on Diagnostic and Statistical Manual (DSM-IV-TR) criteria. Multisite, population-based data from the Autism and Developmental Disabilities Monitoring (ADDM) Network were analyzed from areas of Arizona (AZ), Georgia (GA), Maryland (MD), and South Carolina (SC). Participants were 8-year-old children (born in 1992, 1994, or 1996) in 2000, 2002, or 2004 (and children born in 1988 residing in metropolitan Atlanta in 1996) who had been evaluated for a variety of developmental concerns at education and/or health sources.
Results
From 2000 to 2004, the identified prevalence of the ASDs per 1,000 8-year-old children showed significant increases of 38% in GA and 72% in MD and a nonsignificant increase of 26% in AZ. ASD prevalence was relatively stable in SC with a nonsignificant decrease of 17%. Males had a higher identified prevalence of ASD in all years. Increases among racial, ethnic, and cognitive functioning subgroups varied by site and surveillance year. More children were classified with an ASD by community professionals over time, except in AZ.
Conclusions
There was a trend toward increase in identified ASD prevalence among 8-year-old children who met the surveillance case definition in 3 of the 4 study sites from 2000 to 2004. Some of the observed increases are due to improved ascertainment; however, a true increase in ASD symptoms cannot be ruled out. These data confirm that the prevalence of ASDs is undergoing significant change in some areas of the United States and that ASDs continue to be of urgent public health concern.
aNational Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
bCollege of Medicine, Medical University of South Carolina, Charleston South Caralina 29403, USA
cCollege of Public Health (SP) and Department of Pediatrics (CC and FJM), University of Arizona, Tucson 85724, USA
dDepartment of Epidemiology, Johns Hopkins University, Baltimore, MD 21205, USA
eSchool of Public Health, Drexel University, Philadelphia, PA 19102, USA
fResearch Triangle Institute International, Atlanta, GA 30341, USA
gDepartment of Applied Medical Sciences, University of Southern Maine, Portland, ME 04104, USA
Corresponding author: 1600 Clifton Road, MS E86. Fax: (404) 498-0792.
Financial disclosure: Dr. Rice conducts a limited number of training sessions to professionals on the diagnosis of the autism spectrum disorders as an approved outside activity separate from employment with the Federal government. The other authors report no conflicts of interest. The authors acknowledge the collaborative work of the Autism and Developmental Disabilities Monitoring (ADDM) Network dedicated project staff who contributed to the data collection for this manuscript. The participation and support from the many educational and clinical programs and data sources have been invaluable. Catherine Lord, Ph.D. (University of Michigan), Gail McGee, Ph.D., and Michael Morrier, Ph.D. (Emory University) provided expertise related to the case definition. Diana Schendel, Coleen Boyle, Esther Sumartojo, Ed Trevathan, and Carole Craft reviewed the manuscript and gave editorial assistance. Sydney Pettygrove, Catherine Rice, Jon Baio, Li-Ching Lee, and Joyce Nicholas had full access to all of the data in their study site and take responsibility for the integrity of the data and the accuracy of the data analysis. These projects were funded by the Centers for Disease Control and Prevention (CDC). The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the CDC. For additional information on these projects, see http://www.cdc.gov/autism.
ABSTRACT