Autism prevalence > 1%?

Drawing on the data collected as a part of the US National Survey of Children’s Health, Michael Kogan and colleagues estimated that slightly greater than 1% of children have Autism. The survey asked parents whether a doctor or other health-care provider had said that a child had Autism and the child currently had the condition; the point-prevalence was 110 per 10,000 for Autism Spectrum Disorder. The survey, which is a part of the regular US Child and Adolescent Health Measurement Initiative (CAHMI), asked questions of 78,037 parents.

News of the results hit the major media today, with headlines such as “Did Autism Rates Double?” and “Study: More cases of autism in US kids than previously thought.” Todd Neale of MedPage Today has a sensible story covering the news. As one might have predicted, the Autism bloggers are all over the story. See David Kirby’s take from the Huffington Post. Over on Left Brain/Right Brain Sullivan has a report, too; it includes good discussion of some of the methods of the survey.

Folks who are interested in the actual questions and data can learn more from the National Child Health Survey site. One can actually search the results (once at the site, float over the image shown at the right to click on the 2007 survey, then select the “child health measures” or search for “autism”).

OBJECTIVES The reported increasing prevalence of autism spectrum disorder (ASD) and attendant health and family impact make monitoring of ASD prevalence a public health priority.

METHODS The prevalence of parent-reported diagnosis of ASD among US children aged 3 to 17 years was estimated from the 2007 National Survey of Children’s Health (sample size: 78037). A child was considered to have ASD if a parent/guardian reported that a doctor or other health care provider had ever said that the child had ASD and that the child currently had the condition. The point-prevalence for ASD was calculated for those children meeting both criteria. We examined sociodemographic factors associated with current ASD and with a past (but not current) ASD diagnosis. The health care experiences for children in both ASD groups were explored.

RESULTS The weighted current ASD point-prevalence was 110 per 10,000. We estimate that 673,000 US children have ASD. Odds of having ASD were 4 times as large for boys than girls. Non-Hispanic (NH) black and multiracial children had lower odds of ASD than NH white children. Nearly 40% of those ever diagnosed with ASD did not currently have the condition; NH black children were more likely than NH white children to not have current ASD. Children in both ASD groups were less likely than children without ASD to receive care within a medical home.

CONCLUSIONS The observed point-prevalence is higher than previous US estimates. More inclusive survey questions, increased population awareness, and improved screening and identification by providers may partly explain this finding.

Kogan, M. D., Blumberg, S. J., Schieve, L. A., Boyle, C. A., Perrin, J. M., Ghandour, R. M., Singh, G. K., Strickland, B. B., Trevathan, E., and van Dyck, P. C. (2009). Prevalence of parent-reported diagnosis of autism spectrum disorder among children in the US, 2007. Pediatrics, 124(5).

The electronic version appeared today; it is due to be published on paper in the November issue of the journal.

Michael Kogan is affiliated with the Office of Data and Program Development in the Maternal and Child Health Bureau of the US Health Resources and Services Administration, as are most of the other authors.