Autism Spectrum Disorders Affect About 1 Percent of U.S. Children

A national survey of parents has found the prevalence of autism spectrum disorders (ASDs) is about 1 percent of U.S. children.

The study, "The Prevalence of Parent-Reported Diagnosis of Autism Spectrum Disorder Among children in the United States, 2007," published in the Oct. 5 issue of Pediatrics, draws on data from the 2007 National Survey of Children's Health, a telephone survey of parents conducted jointly by the Health Resources and Services Administration and by the Centers for Disease Control and Prevention's National Center for Health Statistics.

More than 78,000 parents of children between the ages of 3 and 17 were asked whether they had ever been told by a health care provider that their child had autism, Asperger disorder, pervasive developmental disorder (PDD), or other autism spectrum disorder. If parents said yes, they were asked if their child currently had an ASD and to indicate how severe the condition is.

Based on these parent reports, the prevalence of ASD was 110 per 10,000 children (or 1 in 91), representing an estimated 637,000 children ages 3 to 17 with a current diagnosis of ASD in 2007. This is higher than the previous estimate from the Autism and Developmental Disabilities Monitoring (ADDM) Network, which reported autism rates of 66 per 10,000 children (or 1 in 150) among 8-year-olds in 2002.

Researchers suggest the increased prevalence might be partly explained by methodological differences between the surveys, with the inclusion of Asperger disorder, PDD and other ASD, as well as overall increases in public awareness and identification of ASD. Previous studies have shown the average age of diagnosis is decreasing, which leads to an increase in total prevalence at any one point in time.

Odds for having autism were four times higher for boys than for girls, and white children were more likely than black children or multiracial children to have autism. Parents of half the children with ASD described the condition as "mild." Another third of parents described their child's condition as moderate, and the remaining parents described it as severe.

About 38 percent of the children who were ever diagnosed with ASD were reported by their parents to no longer have that diagnosis. Researchers propose several possible explanations, including the imprecision and difficulty of diagnosing very young children, who may no longer meet the criteria for ASD as they age. Children who had "lost" their autism diagnosis were more likely to be diagnosed with other developmental or mental health conditions, such as attention-deficit/hyperactivity disorder, anxiety problems, or behavioral problems.

Children diagnosed with ASD were also significantly less likely than other children to receive care in a medical home, and they had more problems obtaining referrals and coordinating their care.