A growing number of young children are being evaluated for autism spectrum disorder well before they start school—but autism prevalence is still higher among older children, which suggests that health professionals still have work to do on early screening and diagnosis, according to a study published this month in the Journal of Developmental and Behavioral Pediatrics.
Researchers found that autism prevalence among 4-year-olds was 13.4 per 1,000 children. Among 8-year-olds, autism prevalence was 14.7 per 1,000 children. Four-year-olds, who in this study were born in 2006, tended to be diagnosed earlier, at 27 months. Eight-year-olds, who in this study were born in 2002, were diagnosed at a median age of 32 months. That finding suggests that over a four-year time span, early evaluation became more widespread.
The difference in age at diagnosis is important, researchers said, because evidence points to better outcomes for autistic children who get appropriate services early. The American Academy of Pediatrics recommends that children be screened for autism at 18 months and at 2 years, with a full evaluation if the screening tool raises any red flags.
Autism is a developmental disability that can cause significant communication and behavior challenges. According to the CDC, 1 in 68 children are diagnosed with autism spectrum disorder.
Assessing Autism Prevalence
The findings came from the Autism and Developmental Disabilities Monitoring Network, a project of the Centers for Disease Control and Prevention. Eight-year-olds in 11 communities are being monitored; this particular study focused on 5 communities which are tracking 4-year-olds in addition to 8-year-olds. A link to the study can be found at Prevalence and Characteristics of Autism Spectrum Disorder Among 4-Year-Old Children in the Autism and Developmental Disabilities Monitoring Network.
The five communities differed in what records were available to the CDC. In some communities, the CDC had access only to medical records. In other communities, the CDC was able to look both at medical records and at educational records to determine how often autism was showing up among children. In the areas where both medical and educational records were available, more children were found to have autism—a finding that suggests schools play an important diagnostic role, the study said.
The study also found some racial and gender disparities among autism prevalence. Among 4-year-olds, boys were less likely to be evaluated compared to girls. Black children were less likely to be evaluated early compared to white children. However, among black and white children, the disparities were smaller when the autism symptoms also came with cognitive impairments.
A version of this news article first appeared in the On Special Education blog.