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A Report from the Autism and Developmental Disabilities Monitoring (ADDM) Network

What is the Autism and Developmental Disabilities Monitoring (ADDM) Network?
The ADDM Network is a group of programs funded by the Centers for Disease Control and Prevention (CDC) to determine the prevalence of the Autism Spectrum Disorders (ASDs) in United States communities. Its goals are: 

o provide baseline data about ASD prevalence (how common ASDs are in a specific place and time).

• To describe the population of children with ASDs.
• To compare ASD prevalence in different groups of children and different areas of the country.
• To identify changes in ASD prevalence over time.
• To understand the impact of autism and related conditions in U.S. communities.

The ADDM Network’s first two ASD prevalence reports were released in the February 9, 2007, issue of the Morbidity and Mortality Weekly Report Surveillance Summaries.

Six ADDM sites evaluated the prevalence of ASDs for children who were eight years old in 2000 (born in 1992).  An additional eight sites determined ASD prevalence for children who were eight in 2002 (born in 1994). The ADDM Network determines ASD prevalence through the review of health and education records in collaboration with state health departments, diagnostic facilities, and school systems in the specified areas.

By studying the prevalence of ASDs over several time points, we can find out if the number of children with ASDs is rising, dropping, or staying the same in these areas. We can also compare the number of children with ASDs in different areas or groups of people studied in the ADDM Network data. This information can help us look for causes of ASDs.

Autism and Developmental Disabilities Monitoring (ADDM) Network

What do the ADDM Network findings tell us?
The average ASD prevalence was 6.7 per 1,000 for 8-year-olds in 2000 and 6.6 per 1,000 8-year-olds in 2002 in several areas of the United States. That’s about 1 in 150 children in these communities. Most ADDM Network sites found 5.2 to 7.6 per 1,000 eight-year-old children with ASDs in 2002. The prevalence was much lower (3.3 per 1,000) in Alabama and higher (10.6 per 1,000) in New Jersey in 2002. Prevalence stayed the same from 2000 to 2002 in four of the six sites with data for both years. It rose slightly in Georgia and significantly in West Virginia, indicating the need for tracking prevalence over time.

More information about the 2000 surveillance year

• Approximately 4.5 percent of U.S. eight-year-old children (i.e., children born in 1992) from six states - Arizona, Georgia, Maryland, New Jersey, South Carolina and West Virginia.  A total of 1,252 eight-year olds were identified as having an ASD.
• Six sites collected data: Arizona (one county including metro Phoenix), Georgia (five counties in metro Atlanta), Maryland (four counties plus Baltimore City), New Jersey (four counties including the city of Newark), South Carolina (23 counties in the Coastal and PeeDee regions), and West Virginia (entire state).
• Prevalence of ASDs among eight-year-old children ranged from 4.5 per 1,000 (West Virginia) to 9.9 per 1,000 (New Jersey) with the other four sites from 5.5 to 6.5 children with ASD per 1,000 eight-year-old children.  (Average across all six sites was 6.7 per 1,000 children.)
• ASD prevalence was higher among boys than among girls, ranging from three to more than five boys for every girl with ASD.
     - Boys: 6.6 per 1,000 (West Virginia) to 14.6 per 1,000 (New Jersey)
     ­   Girls: 2.0 per 1,000 (Georgia) to 4.2 per 1,000 (New Jersey)
• ASD prevalence among white non-Hispanic children ranged from 4.5 per 1,000 (West Virginia) to 11.0 per 1,000 (New Jersey). For black non-Hispanic children, ASD prevalence ranged from 5.3 per 1,000 (Georgia) to 10.6 per 1,000 (New Jersey).
• The median age of earliest ASD diagnosis ranged from four years, four months (New Jersey and West Virginia) to four years, eight months (Georgia). But, for 69 –88 percent of children with an ASD, concerns about the child’s development had been recorded before three years of age.

More information about the 2002 surveillance year

• Approximately 10 percent of U.S. eight-year-old children (i.e., children born in 1994), from 14 states - Alabama, Arizona, Arkansas, Colorado, Georgia, Maryland, Missouri, New Jersey, North Carolina, Pennsylvania, South Carolina, Utah, West Virginia and Wisconsin.  A total of 2,685 eight-year-olds were identified as having an ASD.
• Fourteen sites collected data: Alabama (32 counties), Arizona (one county including metro Phoenix), Arkansas (entire state), Colorado (two counties in metro Denver), Georgia (five counties in metro Atlanta), Maryland (four counties plus Baltimore City), Missouri (five counties in metro St. Louis), New Jersey (four counties including the city of Newark), North Carolina (eight central counties), Pennsylvania (Philadelphia County), South Carolina (23 counties in the Coastal and PeeDee regions), Utah (three counties around metro Salt Lake City), West Virginia (entire state), Wisconsin (10 counties in the southeast including Milwaukee)
• ASD prevalence among eight-year-old children was 3.3 per 1,000 (Alabama) to 10.6 per 1,000 (New Jersey). But, 12 of the 14 sites had a closer range of 5.2 to 7.6 per 1,000 children (average across all 14 sties was 6.6 per 1,000 eight-year-old children).
• In 2002, four sites (Alabama, Missouri, Pennsylvania and Wisconsin) relied on information from health sources. On average, the prevalence was lower in those sites than in the other 10 sites that combined information from health and education sources. In both study years, many ASD cases were found through education sources alone.
• ASD prevalence was higher among boys than among girls, ranging from more than three to more than six boys for every girl with ASD.
     - Boys: 5.0 per 1,000 (Alabama) to 16.8 per 1,000 (New Jersey)
     - Girls: 1.4 per 1,000 (Alabama) to 4.0 per 1,000 (New Jersey)
• ASD prevalence among white non-Hispanic children ranged from 3.3 per 1,000 (Alabama) to 12.5 per 1,000 (New Jersey). For black non-Hispanic children, ASD prevalence ranged from 3.4 per 1,000 (Alabama) to 7.7 per 1,000 (New Jersey). Among Hispanic children, it ranged from 0.3 per 1,000 (Wisconsin) to 9.7 per 1,000 (New Jersey).
• The median age of earliest ASD diagnosis ranged from four years, one month (Utah) to five years, six months (Alabama). But for 51–91 percent of children with an ASD, developmental concerns had been recorded before three years of age. 

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Date: February 08, 2007
Content source: National Center on Birth Defects and Developmental Disabilities