UNC study shows state autism rates in line with national average

The survey was conducted by the CDC’s Autism and Developmental Disabilities Monitoring Network to accurately estimate of the number of children affected by autism spectrum disorder (ASD). Researchers in 14 states combined data from numerous sources, including schools, medical facilities, and government service agencies, to determine the most comprehensive estimate of the number and characteristics of children with autism to date.

Photograph of Dr. Julie Daniels

“We collected information from multiple agencies to ensure we were looking at the complete picture,” said Dr. Julie Daniels, assistant professor of epidemiology and maternal and child health at the UNC School of Public Health. “It’s critical that school officials, service providers, doctors, parents and anyone who sets policies affecting these children have an accurate estimate of the need so they can more effectively plan for the future.”

The data provide important information on the current prevalence of ASD and will be used to examine trends over time, according to the CDC. The prevalence estimates can also help communities approximate how many children may need services and intervention.

Autism spectrum disorders are developmental disabilities defined by considerable impairments in social interaction and communication and the presence of unusual behaviors and interests. They can sometimes be diagnosed as early as 18 months and last throughout a person’s life. ASDs include autistic disorder, pervasive developmental disorder (including atypical autism) and Asperger syndrome. Early intervention may improve the prognosis for children with autism, but help is often needed throughout life.

The North Carolina counties included in the survey were: Alamance, Chatham, Davidson, Durham, Forsyth, Guilford, Orange and Randolph. More than 3,000 records were screened for indicators of a possible autism spectrum disorder. Researchers focused on collecting accurate data for children 8 years old. “By age 8, most children have been diagnosed and use some publicly available services,” Daniels said. “ASD can be difficult to diagnosis, and if you consider only very young children, you’re likely only to find the most severely affected cases.”

Highlights of the North Carolina results show:

• One in 154 children born in 1994 and living in the study area in 2002 met the CDC criteria for an autism spectrum disorder.
• Autism affects more boys than girls (five boys diagnosed for every one girl). This ratio was slightly higher in North Carolina than in other states.
• Less than half of the children (47 percent) with an ASD also had a cognitive impairment; 23 percent were of borderline intelligence (IQ 71-85); 23 percent were of average intelligence; and five percent had above-average intelligence.
• 90 percent of the 8 year olds with ASD were served through the state’s exceptional children program.

While these studies did not investigate the causes of these disorders, the CDC’s Centers for Autism and Developmental Disabilities Research and Epidemiology Network is beginning a multi-state collaborative study to help identify factors that may put children at risk for ASDs and other developmental disabilities, Daniels said. UNC is one of six sites participating and will begin enrolling children ages 2 to 5 years old later this spring.

Complete results of the survey are available in the Feb. 9 edition of “Morbidity and Mortality Weekly Report,” CDC’s weekly publication, available on-line at www.cdc.gov/mmwr.

Agencies participating in the North Carolina survey include the N.C. Department of Public Instruction, Division TEACCH (Treatment and Education of Autistic and related Communication-handicapped Children), Child Development Service Agencies of the N.C. Department of Health and Human Services and the Clinical Center for the Study of Development & Learning at UNC.

Note: Julie Daniels can be reached at 919-966-7096 or julie_daniels@unc.edu.

UNC School of Public Health contact: Ramona DuBose, (919) 966-7467, ramona_dubose@unc.edu.

UNC News Services contact: Becky Oskin, (919) 962-8596, becky_oskin@unc.edu.