New findings from the Centers for Disease Control and Prevention (CDC) demonstrate that the prevalence of autism spectrum disorder (ASD) in the United States has increased. According to the report, as many as 1 in 45 children—over two percent—have ASD. Previous research found that 1 in 68 children had ASD. The research team says that the findings indicate that the increased prevalence is likely due to the method of data collection.
Data from the 2014 National Health Interview Survey (NHIS) demonstrate that 2.24 percent of children in the US have received a diagnosis of ASD at some point.
The research team changed the way it conducted interviews for the 2014 NHIS. In previous years, researchers asked parents if a doctor or health professional had ever told them that their child had a developmental delay. The parent was then asked to review a list of 10 conditions and report which their child had. In 2014, the researchers asked about ASD first, then followed up with questions about other developmental delays. The new methodology likely accounts for the increase in prevalence.
Prevalence in ASD rose, but the prevalence of other conditions fell. Parent reports of “other developmental delays” dropped by 26 percent (from 4.84 percent to 3.57 percent) compared to the 2011-2013 survey. The researchers suggest that the parents who reported other developmental delays in the past are now reporting diagnoses of ASD.
It is possible that the data overstate the true prevalence of ASD. By asking parents if their child has “ever” been diagnosed with ASD, the survey does not account for children who had ASD in the past, but may not have it now. Effective treatments, misdiagnosis, or maturation could lead to children losing an autism diagnosis.
This research was prepared by researchers from the National Center for Health Statistics and the National Center on Birth Defects and Developmental Disabilities.
Previous news in autism:
- Adults with autism likely to have health problems
- Reclassification may account for autism prevalence