CDC - Data and Statistics, Autism Spectrum Disorders

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Data & Statistics

CDC Statement on Autism Data

October 5, 2009

CDC recognizes the importance of the data released today in Pediatrics by the Health Resources and Services Administration (HRSA) on parental report of autism from the National Survey of Children’s Health.

An updated prevalence report from CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network is currently in press. Given the importance of the issue and these new findings, we would like to confirm that updated preliminary data from CDC shows that overall prevalence findings are similar to those reported by HRSA indicating that approximately 1% of children are affected with an ASD. There is some variation in ASD prevalence among the ADDM Network communities, which will be described in detail in the upcoming report. We expect to make the CDC report available in its entirety later this year in accordance with publication guidelines.

CDC joins with HRSA in recognizing that ASDs are conditions of urgent public health concern and these data affirm that a concerted and substantial national response is warranted. We will continue to research potential risk factors associated with ASDs and will continue our work in surveillance so that we can understand trends in ASD rates over time. We hope that these new data might raise awareness about ASDs to help improve early identification and intervention and to provide information for policy and service planning, which will ultimately help to meet the growing needs of individuals, families, and communities affected by ASDs

For more information on the coordination of public and private research on autism: Interagency Autism Coordinating Committee (IACC)

Prevalence

It is estimated that between 1 in 100 and 1 in 300 with an average of 1 in 150 children in the United States have an ASD. [Read article]
ASDs are reported to occur in all racial, ethnic, and socioeconomic groups, yet are four to seven times more likely to occur in boys than in girls. However, we need more information on some less studied populations and regions around the world. [Read article]
If 4 million children are born in the United States every year, approximately 26,670 children will eventually be diagnosed with an ASD. Assuming the prevalence rate has been constant over the past two decades, we can estimate that about 560,000 individuals between the ages of 0 to 21 have an ASD.
Studies in Asia, Europe and North America have identified individuals with an ASD with an approximate prevalence of 0.6% to over 1%. [Data table]
Approximately 13% of children have a developmental disability, ranging from mild disabilities such as speech and language impairments to serious developmental disabilities, such as intellectual disabilities, cerebral palsy, and autism. [Read summary]

Learn more about prevalence of ASDs »

Risk Factors and Characteristics

Studies have shown that among identical twins, if one child has an ASD, then the other will be affected about 60-96% of the time. In non-identical twins, if one child has an ASD, then the other is affected about 0-24% of the time. ^[1]
Parents who have a child with an ASD have a 2%–8% chance of having a second child who is also affected. ^[1]
It is estimated that about 10% of children with an ASD have an identifiable genetic, neurologic or metabolic disorder, such as fragile X or Down syndrome. As we learn more about genetics, the number of children with an ASD and an identifiable genetic condition will likely increase. [Read summary] [Read summary]
A study published by CDC in 2007, found that 33-59% of the children who had an ASD also had an Intellectual Disability (intelligence quotient <=70). [Read article]

Percentages of children aged 8 years with and without cognitive impairment, by intelligence quotient (IQ) score, site, and sex – Autism and Developmental Disabilities Monitoring Network, 14 sites,* United States, 2002

"Graph: Percentages of children aged 8 years with and without cognitive impairment, by intelligence quotient (IQ) score, site, and sex – Autism and Developmental Disabilities Monitoring Network, 14 sites,* United States, 2002"

[D]

Studies show that 5% of people with an ASD are affected by fragile X and 10% to 15% of those with fragile X show autistic traits. [Read summary]
One to four percent of people with ASD also have tuberous sclerosis. [Read summary]
About 40% of children with an ASD do not talk at all. Another 25%–30% of children with autism have some words at 12 to 18 months of age and then lose them. Others may speak, but not until later in childhood. ^[2]

Diagnosis

The median age of earliest ASD diagnosis is between 4.5 and 5.5 years, but for 51–91 percent of children with an ASD, developmental concerns had been recorded before three years of age. [Read article]
Studies have shown that about one third of parents of children with an ASD noticed a problem before their child’s first birthday, and 80% saw problems by 24 months. [Read summary]

Research has shown that a diagnosis of autism at age 2 can be reliable, valid, and stable. ^[1] But despite evidence that ASDs can often be identified at around 18 months, many children do not receive final diagnoses until they are much older. [Read summary]

Economic Costs

Recent studies have estimated that the lifetime cost to care for an individual with an ASD is $3.2 million. [Read summary]
Individuals with an ASD had average medical expenditures that exceeded those without an ASD by $4,110–$6,200 per year. On average, medical expenditures for individuals with an ASD were 4.1–6.2 times greater than for those without an ASD. Differences in median expenditures ranged from $2,240 to $3,360 per year with median expenditures 8.4–9.5 times greater. [Read summary]

References

Boyle C, Van Naarden Braun K, Yeargin-Allsopp M. The Prevalence and the Genetic Epidemiology of Developmental Disabilities. In: Genetics of Developmental Disabilities. Merlin Butler and John Meany eds. 2005.
Johnson, C.P. Early Clinical Characteristics of Children with Autism. In: Gupta, V.B. ed: Autistic Spectrum Disorders in Children. New York: Marcel Dekker, Inc., 2004:85-123.