Autism may be more common than previously thought. In fact, it may even affect as many as one in 150 U.S. children, according to a recent report by the Centers for Disease Control and Prevention (CDC).
Whether this is actually the case remains to be seen. Experts point to other factors for the increased reporting of autism and the need for further research.
The new CDC report, however, is the largest and most comprehensive summary of prevalence data yet, combining data from two separate studies conducted in fourteen states. The study aimed to estimate how widespread autism spectrum disorder (ASD) is among American children. ASD is a term that incorporates not only the classical form of autism, but also closely related disabilities. ASD includes: Pervasive Developmental Disorder—Not Otherwise Specified (PDD-NOS), which contains several features that resemble autism, but may not be as severe; Rett’s syndrome, which affects girls and is genetic with a neurological component; and Asperger’s syndrome, referring to individuals with some autistic symptoms, but with intact language abilities. Some physicians include other disorders under the ASD umbrella as well, including Childhood Disintegrative Disorder, which refers to children who appear to develop normally for the first few years of life, but then regress suddenly and dramatically with loss of speech and the development of autistic characteristics. Often, the terms for the classical form of autism and ASD are now used interchangeably.
Six sites evaluated the prevalence of ASD in 2000, and another eight sites looked at the prevalence of ASD in 2002. ASD cases were identified through review of health and education records of eight-year-old children, as research had shown most children had been diagnosed by that age.
The results showed an average of 6.7 children out of 1,000 had an ASD in the six communities assessed in 2000, and an average of 6.6 children out of 1,000 had a form of autism in the fourteen communities included in the 2002 study.
The authors concluded that the study “confirms that ASDs are more common than previously thought and are conditions of urgent public health concern.”
Although the study reports higher rates of autism than in previous years—6.6 to 6.7 per 1,000 children as compared to 5.5 per 1,000 from last year—it doesn’t necessarily mean the incidence of autism is increasing.
Wider access to records and better data may be one reason the estimates have increased, but experts also suggest that an increase in awareness of these disorders and a broadening of the ASD diagnosis to a wider range of symptoms may have contributed to the higher estimate.
