Prevalence of Autism in a US Metropolitan Area

Abstract

Context Concern has been raised about possible increases in the prevalence of autism. However, few population-based studies have been conducted in the United States.Objectives To determine the prevalence of autism among children in a major US metropolitan area and to describe characteristics of the study population. Design, Setting, and PopulationStudy of the prevalence of autism among children aged 3 to 10 years in the 5 counties of metropolitan Atlanta, Ga, in 1996. Cases were identified through screening and abstracting records at multiple medical and educational sources, with case status determined by expert review.Main Outcome Measures Autism prevalence by demographic factors, levels of cognitive functioning, previous autism diagnoses, special education eligibility categories, and sources of identification.Results A total of 987 children displayed behaviors consistent with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for autistic disorder, pervasive developmental disorder-not otherwise specified, or Asperger disorder. The prevalence for autism was 3.4 per 1000 (95% confidence interval [CI], 3.2-3.6) (malefemale ratio, 4:1). Overall, the prevalence was comparable for black and white children (black, 3.4 per 1000 [95% CI, 3.0-3.7] and white, 3.4 per 1000 [95% CI, 3.2-3.7]). Sixty-eight percent of children with IQ or developmental test results (N=880) had cognitive impairment. As severity of cognitive impairment increased from mild to profound, the male-female ratio decreased from 4.4 to 1.3. Forty percent of children with autism were identified only at educational sources. Schools were the most important source for information on black children, children of younger mothers, and children of mothers with less than 12 years of education. ConclusionThe rate of autism found in this study was higher than the rates from studies conducted in the United States during the 1980s and early 1990s, but it was consistent with those of more recent studies.

Brain‐derived neurotrophic factor and autism: maternal and infant peripheral blood levels in the Early Markers for Autism (EMA) study

“…Following a protocol initially developed by the Metropolitan Atlanta Developmental Disabilities Surveillance Program [Yeargin-Allsopp et al, 2003] …”

Comparison Groups in Autism Family Research: Down Syndrome, Fragile X Syndrome, and Schizophrenia

“…Whereas families whose child has Down syndrome are aware of this diagnosis at birth (and sometimes even before birth), this is not the case in autism, which is generally not diagnosed until between age 3 and 4 (Yeargin- Allsopp et al, 2003). Furthermore, whereas Down syndrome is a certain diagnosis, confirmed by genetic testing, the diagnosis of autism is ambiguous because it relies on behavioral criteria and in some cases remains uncertain in the eyes of families throughout the life course.…”

Proteomic studies identified a single nucleotide polymorphism in glyoxalase I as autism susceptibility factor

“…Individuals with autism exhibit a wide spectrum of cognitive abilities, with about 30% displaying severe developmental delay and a significant proportion also experiencing epileptic seizures. The prevalence of this disability in the general population is over 1 in 1, 000 live births [Fombonne, 2002], although a recent estimate indicate three times higher prevalence rate [Yeargin-Allsopp et al, 2003]. Generally, boys are three to four times more commonly affected than girls.…”