More children in the United States have an autism spectrum disorder (ASD) than previously thought, the US Centers for Disease Control and Prevention (CDC) reports today.
New estimates put the figure at 1 in 68 children aged 8 years (or 14.7 per 1000) ? roughly 30% higher than previous estimates reported in 2012 of 1 in 88 children (11.3 per 1000) having an ASD, the agency said.
"The criteria used to diagnose ASDs and the methods used to collect data have not changed," the CDC noted.
The new estimatesΒ are publishedΒ in the March 28 issue of the Morbidity and Mortality Weekly Report.
"The number of children identified with autism continues to rise," Coleen Boyle, PhD, director of CDC"s National Center on Birth Defects and Developmental Disabilities, said during a telebriefing with reporters today.
"Over the last decade, the most notable change in the characteristics of children identified with autism is the growing number who have average or above average intelligence, from one third in 2002 to nearly 50% in 2010," Dr. Boyle said.
"To better understand why, there is an urgent need to do more research. It could be that doctors are getting better at identifying these children. There could be a growing number of children with autism and higher intellectual ability, or it may a combination of better recognition and increased prevalence," she added.
The new estimates are based on 2010 data from 11 sites participating in the Autism and Developmental Disabilities Monitoring (ADDM) Network, an active surveillance system that provides estimates of the prevalence of ASD and other characteristics among children aged 8 years.
They chose age 8 because "most children who are diagnosed with autism will be diagnosed by age 8, based on previous data," Dr. Boyle explained.
For 2010, the overall prevalence of ASD among the ADDM sites was 14.7 per 1000 (1 in 68) children aged 8 years.
Overall ASD prevalence estimates varied among sites from 5.7 to 21.9 per 1000 children. ASD prevalence estimates also varied by sex and racial/ethnic group.
The data continue to show that ASD is almost 5 times more common among boys than girls: 1 in 42 boys vs 1 in 189 girls. White children are more likely to be identified as having ASD than are black or Hispanic children, the CDC said.
Among the 7 sites with sufficient data on intellectual ability, 31% of children with ASD were classified as having IQ scores in the range of intellectual disability (IQ <= 70), 23% in the borderline range (IQ = 71 - 85), and 46% in the average or above average range of intellectual ability (IQ > 85).
"The study found that almost half of children identified with ASD have average or above average intellectual ability (an IQ above 85) compared to a third of children a decade ago," the CDC said.
"Community leaders, health professionals, educators and childcare providers should use these data to ensure children with ASD are identified as early as possible and connected to the services they need," said Dr. Boyle.
The CDC said most children with ASD are diagnosed after age 4, even though ASD can be diagnosed as early as age 2. Healthy People 2020, the nationβs 10-year health objectives, strives to increase the proportion of young children with ASD and other developmental delays who are screened, evaluated, and enrolled in early intervention services in a timely manner.
The most important thing for parents to do is to act early when there is a concern about a childβs development," said Marshalyn Yeargin-Allsopp, MD, chief of CDCs Developmental Disabilities Branch.
New Initiative Announced
Katherine C. Beckman, PhD, MPH, of the US Department of Health and Human Services Administration for Children and Families, announced a new "unprecedented" government-backed initiative launching today that will encourage developmental and behavioral screening for autism and provide support for children, families, and providers who care for children with autism.
The so-calledΒ Birth to 5: Watch Me Thrive!Β program will help families look for and celebrate milestones; promote universal screenings; identify delays as early as possible; and improve the support available to help children succeed in school and thrive alongside their peers, she noted.
The program features "a compendium of first-line research-based screening tools that meet specific quality inclusion criteria [and] an array of resources" for multiple audiences, including early care and education providers, pediatricians, child welfare case workers, families, and communities, Dr. Beckman said.
The American Academy of Pediatrics (AAP) is a partner in the initiative.
"The AAP is working to help make pediatric practices more equipped to provide ongoing care to the many children with autism," James Perrin, MD, FAAP, president of the AAP, said in a statement. "These rising rates [announced today] certainly underscore the need to improve our understanding of the causes of autism and to work on prevention," he added.
"The prevalence data makes even more important the Academyβs focus on early screening, identification, and referral for intervention for all children and our work to support collaborative medical homes for children, youth, and adults with autism spectrum disorder," added Susan Hyman, MD, FAAP, chair of the AAP autism subcommittee.
"Itβs critical that we as a society do not become numb to these numbers," Dr. Hyman said. "They remind us of the work we need to do in educating clinicians and parents in effective interventions for all children, including those with developmental disabilities."