The US Centers for Disease Control and Prevention (CDC) assess the prevalence of Autism Spectrum Disorders (ASDs) in 14 communities throughout the States at 1 in 150 children. And in the majority of cases the signs are picked up before the children reach the age of 3.
The two studies that led to this finding are published in the CDC’s Morbidity and Mortality Weekly Report (MMWR).
“Our estimates are becoming better and more consistent, though we can’t yet tell if there is a true increase in ASDs or if the changes are the result of our better studies,” said CDC Director Dr. Julie Gerberding. “We do know, however, that these disorders are affecting too many children.”
The two studies, one from 2000 data and the other from 2002 data are the first and largest summary of prevalence data from multiple US communities taking part in an autism spectrum disorder (ASD) surveillance project. Their findings show that in the year 2000, an average of 6.7 of 8-year olds out of 1,000 had an ASD in 6 communities, and in 2002 this figure was 6.6 of 8-year olds out of 1,000 in 14 communities.
Overall, the two sets of figures translate to an average finding of approximately 1 in 150 of 8-year olds having an ASD in these communities. In the year 2000 for 6 communities the rates ranged from 1 in 222 to 1 in 101 children. And the figures for the year 2002 range from 1 in 303 to 1 in 94 in 14 communities.
The CDC stress that these figures do not constitute a national estimate, but they do confirm that ASDs are more prevalent in the areas surveyed than previously thought.
They counted 8-year olds because this is the age by which most children with ASD have been identified for receipt of services.
These findings are consistent with the upper ranges estimated in other studies.
Studies from other countries using current diagnostic criteria with a range of methods have shown a range of ASD prevalence of between 1 in 500 and 1 in 166 children.
Dr Marshalyn Yeargin-Allsopp, chief of CDC’s autism program said that it was extremely difficult to make accurate estimates of ASD prevalence in children, “Medical records often do not provide such information, and identification is often made by schools or education specialists,” she said. And she added that the data in these reports, which has been provided by the Autism and Development Disabilities Monitoring (ADDM) Network, “was designed to provide more consistent and reliable estimates.”
The surveys also looked at when the signs of ASDs had first been noticed by parents and others in the early stages of the children’s development. They found that documented concerns existed for between 51 and 88 per cent of children with ASDs before they had reached 3 years of age and that 50 per cent of children had been diagnosed between 6 months before and 6 months after their 5th birthday.
The concerns that had been most commonly expressed and written down were about language development, followed by social development.
“It is important for parents, health care professionals and childcare providers to recognize developmental milestones such as smiling, pointing and waving bye-bye,” said Dr Yeargin-Allsopp. “It’s also important that health care professionals give children routine developmental and autism-specific screenings,” she added. She also said the causes of ASD are still unknown, but early detection and diagnosis is the best way to ensure children receive the appropriate support.
Autism Spectrum Disorders (ASDs) are disabilities of development characterised by impairments in social ability, language and communication and unusual or repetitive behaviour. ASDs can be diagnosed at 18 months. The condition lasts for the whole of a person’s life. ASDs include autistic disorder, pervasive development disorder – not otherwise specified (PDD-NOS), including atypical autism, and Asperger Syndrome (AS).
The CDC’s Centers for Autism and Development Disabilities Research and Epidemiology (CADDRE) Network is doing a multi-state study to find out what puts children at risk for ASDs and other developmental disabilities.
The CDC has also launched a public awareness campaign titled “Learn the Signs. Act Early” to help parents and educators track the emotional and social development of children and spot any early signs of ASD.
“Prevalence of Autism Spectrum Disorders — Autism and Developmental Disabilities Monitoring Network, Six Sites, United States, 2000.”
Catherine Rice et al. (CDC).
MMWR CDC Surveillance Summaries, February 9, 2007, Vol. 56, No. SS-1
“Prevalence of Autism Spectrum Disorders — Autism and Developmental Disabilities Monitoring Network, 14 Sites, 2002.”
Catherine Rice et al. (CDC).
MMWR CDC Surveillance Summaries, February 9, 2007, Vol. 56, No. SS-1
Written by: Catharine Paddock
Writer: Medical News Today