NEW YORK — Developmental disabilities among American children increased 17 percent in the past decade led by a rise in autism and attention deficit hyperactivity disorder, a U.S. government study found.
The prevalence of the developmental disorders rose to 15 percent of U.S. children, or about 10 million, in 2006-2008, from 12.8 percent, or about 8 million, in 1997-1999, according to the study from the Centers for Disease Control and Prevention. The research is published in the journal Pediatrics.
Researchers said the increase may be due in part to more preterm births and parents having children at older ages. They also said that improvements in screenings, diagnosis and awareness have pushed the numbers higher. About one in six children in the U.S. now have a developmental disability, and that will likely increase demand for health and education services, researchers said.
“Because the prevalence of some of these developmental disabilities is increasing, there’s going to be an increased demand on the health system for these kind of specialized medical services,” Sheree Boulet, the study author and an epidemiologist at the Atlanta-based CDC’s National Center on Birth Defects and Developmental Disabilities, said in a May 20 telephone interview.
The study is the first to document the prevalence of developmental disabilities in U.S. children since 1994, Boulet said.
The researchers looked at data on children ages 3 to 17 years from the 1997 to 2008 National Health Interview Surveys. The surveys are representative samples of U.S. households and asked parents to report diagnoses of ADHD, mental retardation, cerebral palsy, autism, seizures, stuttering or stammering, moderate to profound hearing loss, blindness, learning disorders and other developmental delays.
Autism, a lifelong and disabling condition caused by abnormal brain development, had the largest increase over the study, rising nearly fourfold to 0.74 percent of children in 2006-2008 from 0.19 percent in 1997-1999, the paper showed. The disorder hinders a person’s ability to communicate and engage in social interactions.
They found that the number of children with ADHD rose 33 percent during the period to 7.6 percent from 5.7 percent. The disorder was “chiefly responsible” for the higher overall incidence of developmental disabilities in the U.S., the authors wrote.
Michael Rosanoff, associate director of Public Health Research and Scientific Review for the nonprofit advocacy group Autism Speaks in New York, said some of the increase in autism could be explained by better diagnosis, more awareness by parents and doctors and less stigma surrounding the condition making parents more likely to report their children having the condition. Still, more studies are needed to identify the environmental factors that may cause autism, he said.
“From this information, the federal government can see that developmental disabilities are more prevalent than previously believed and that resources should be allocated accordingly for dealing with these conditions,” he said in a May 20 telephone interview.
The study also found a number of children with moderate to profound hearing loss declined 31 percent.
Boys were more likely than girls to have developmental disabilities, while low-income families and those on public health insurance had a higher likelihood of having children with the disorders, the study found.
Autism varies in severity and symptoms. Those with the condition may have trouble making eye contact, understanding facial expressions, and learning to share and follow instructions. Children with the disorder also may show compulsive interests or behaviors.
Andrew Adesman, chief of Developmental & Behavioral Pediatrics at Cohen Children’s Medical Center in New Hyde Park, New York, said families need to speak to their doctors if they are concerned about their children and make sure they get the services they need. Adesman wasn’t an author on today’s paper.
“Realistically kids aren’t going to get better on their own and they need the benefit of services,” he said in a May 20 telephone interview. “There is a danger that at a time when numerically there seems to be an increased number of children with problems, many governments are looking to scale back and reduce services. That certainly is undesirable.”
More studies are needed to identify preventable causes of the disabilities and the benefits of early services for children with developmental disorders, Boulet said. The CDC also plans a follow-up study in the future to see if the prevalence of these disorders continues to rise.