Autism Spectrum Disorders in Preschool-Aged Children: Prevalence and Comparison to a School-Aged Population
Received 31 December 2008; accepted 27 April 2009. published online 22 June 2009.
Purpose
The purpose of this study was to determine the prevalence and case characteristics of children with autism spectrum disorders (ASDs) among 4-year-olds and to compare findings to previous prevalence estimates for 8-year-olds in the same geographic area.
Methods
South Carolina (SC) has been a participant in the Centers for Disease Control and Prevention's active, population-based, multiple-site ASD surveillance network for 8-year-olds since 2000. The 8-year-old methodology, designed to identify children both with and without prior diagnosis, was applied in SC with modification to include information sources for younger children.
Results
The ASD prevalence among 4-year-olds in 2006 was 8.0 per 1000 (95% confidence interval [CI], 6.1–9.9), or 1 in 125. In comparison, ASD prevalence among 8-year-olds in the same geographic area was 7.6 (95% CI, 5.7–9.5) in 2000 and 7.0 (95% CI 5.1–8.9) in 2002. Developmental concerns were documented at earlier ages across time, and while most cases received services, only 20% to 29% received services specific to ASD.
Conclusions
Findings should provide useful information for the planning of health/education policies and early intervention strategies for ASD.
aDepartment of Biostatistics, Bioinformatics, and Epidemiology, Medical University of South Carolina, Charleston, SC
bDepartment of Pediatrics, Division of Genetics and Developmental Pediatrics, Medical University of South Carolina, Charleston, SC
Address correspondence to: Joyce S. Nicholas, PhD, Medical University of South Carolina, Department of Biostatistics, Bioinformatics, and Epidemiology, Department of Neurosciences, 135 Cannon St., Suite 303, MSC 835, Charleston, SC 29425-8350. Tel: (843) 876-1132. Fax: (843) 876-1126.
ABSTRACT