The chart above shows the prevalence of autism spectrum disorders in 8-year-old children studied in 2002. According to the CDC's most recent autism prevalence study, Alabama has many fewer children with autism than 13 other states included in this new study. Experts there caution that not all Alabama kids are being counted. (chart source: Centers for Disease Control)
The day after the Centers for Disease Control released new data on the prevalence of autism spectrum disorders showing that Alabama had the lowest rate of autism among children in 14 states studied, specialists in Alabama meeting at an autism conference said they were skeptical of the results because the data doesn't include information from school districts.
"We knew right away that those rates seemed low," said University of Alabama child psychologist Laura Klinger, who participated in a statewide autism conference Friday at the University of Alabama. "I asked everyone to raise their hand if they thought Alabama's autism numbers were half of everybody else. Nobody raised their hand," Klinger told the Associated Press. You can read the AP article here, via the website for a Birmingham, Ala., Fox TV affiliate.
The Centers for Disease Control (CDC) on Feb. 8 released new data on the prevalence of autism spectrum disorders in 8-year-olds born in 1994 based on a study in 14 states and found that about 1 in 150 of the children had some form of autism. That ratio is higher than the widely quoted estimate of 1 child in 166 having some form of autism, based on an earlier study. (Read more background on the latest study here. A PDF file that includes state-by-state summaries and the chart above is available from the CDC's website here.)
The CDC's results indicate that the prevalence of autism diagnoses in Alabama is 3.3 cases per 1,000 children, while the average across the 14 states studied showed a prevalence of 6.6 cases per 1,000 children.
The Associated Press story reported that Alabama medical professionals "said state's numbers were low because researchers had access only to health department records, while most of the other states allowed use of education department records as well. They said Alabama also has fewer autism programs than the other states, limiting the information available. Alabama's autism rates are probably close to the national average, the medical specialists said Friday."
Alabama education officials cited privacy laws in not allowing access to their records, the Associated Press reported. Russell Kirby, a University of Alabama at Birmingham professor who organized Alabama's data collection, told the news organization: "We're fairly well convinced that we missed a lot of cases because of our inability to review records in schools. If we had been able to, the feeling is our numbers would be right in the range that other states had found."
One last note from the AP story: A behavioral scientist who helped author the CDC study said three other states (Missouri, Wisconsin and Pennsylvania) also didn't allow access to school records. But the scientist said the numbers in those states "were still higher than Alabama's because those states had more autism programs and researchers were able to use that information to supplement health records."