May 13, 2011 —
Efforts to increase awareness about the early signs of autism appear to be working, a new study shows.
Researchers with the CDC, Harvard Medical School, and United Health Group found that the number of children younger than age 3 who were enrolled in early intervention programs for autism spectrum disorders (ASD) in Massachusetts rose 66% in children born between 2001 and 2005.
Mounting evidence suggests that the impairments of autism -- including deficits in speech, IQ, and social skills -- can be tempered or even reversed if therapy is started early.
So the government has funded public health campaigns to increase awareness of the first signs of autism and the importance of early diagnosis among parents and health care providers.
Some states, including Massachusetts, have passed laws mandating insurance coverage for early interventions.
Advocacy and professional groups have also ramped up their efforts to encourage early diagnosis, and there's been more media coverage of the disorder, says study researcher Susan E. Manning, MD, MPH, an epidemiologist with the CDC and the Massachusetts Department of Public Health.
Taken together, she says, those efforts are probably responsible for much of the increase observed in the study.
Experts who were not involved in the study say that to the extent the increase in early diagnosis is a reflection of successful public awareness efforts, it is positive news.
"This is exactly what researchers who are working so hard to identify the early markers of autism and to develop these efficacious early interventions want to see happen," says Rebecca Landa, PhD, director of the Center for Autism and Related Disorders at Kennedy Krieger Institute, Baltimore.
But researchers could not rule out the possibility that some of the new diagnoses represented an actual uptick in affected children.
"Some of this could be due to an actual true increase in autism," Manning says, "But how much of that, of the overall increase, is accounted for by a true increase in autism is hard to tease out because all the other factors come into play."
Expansion of Autism Symptom List
Other experts say the increase noted in the study probably also reflects the expansion of symptoms that are used to define autism spectrum disorders. They worry some young children may be getting a diagnosis based on symptoms they'll eventually outgrow.
"Because ASD now includes only a few symptoms of classic autism, children who previously were not diagnosed with ASD are now being identified," says Stephen Camarata, PhD, an autism specialist and professor of hearing and speech sciences at Vanderbilt University in Nashville, Tenn.
Camarata says "late talking," or talking after the age of 2, which affects about 10% of all toddlers, is an example.
"If late talking is now viewed as diagnostic for putting a child on 'the autism spectrum,' then all late talkers will be identified as autistic," Camarata says.
"This is important because, if there is nothing else wrong -- no other symptoms of autism or other disability such as cognitive impairment -- approximately 60%-70% of the late talkers catch up by the time they reach 3 years old," he tells WebMD.
Tracking Early Autism Diagnoses
For the study, researchers cross-referenced data on births in Massachusetts between 2001 and 2005 with records on children enrolled in the state's early-intervention programs for autism spectrum disorders before their third birthday.
The study included 385,631 children without documented autism spectrum disorders and 3,013 enrolled in early-intervention programs.
To be referred to an early-intervention program, children had to have failed a screening test of 23 questions called the modified checklist of autism in toddlers. The test asked questions about a child's ability to interact with others, pretend during play, walk, speak, and hear.
Information on parental characteristics like age, education level, and race, were derived from birth certificates.
Researchers also included information about whether the children were born prematurely or at low birth weights or whether they were single births or multiples.
Autism Incidence: Boys vs. Girls
The incidence of autism spectrum disorders in children less than 3 years of age increased from 56 per 10,000 in children born in 2001 to 93 per 10,000 in children born in 2005.
There was a greater increase in boys than in girls.
Among boys, the early autism diagnoses increased 70% between children born in 2001 and those born in 2005. They went up 39% in girls.
That means boys were about 4.5 times more likely than girls to be given an early diagnosis of autism spectrum disorder.
That's not a huge surprise, researchers say, given that autism is known to be about three to four times more prevalent in boys than in girls.
Low birth weights, premature births, and multiple births were all at increased risk of an early diagnosis of autism spectrum disorder, the study found.
Autism diagnoses were more likely in children born to older mothers, especially those over 45. A father's age or education appeared to have no impact on the likelihood of an autism diagnosis, however.
The study also found something intriguing with regards to race and ethnicity. At the beginning of the study, white children had a higher likelihood of early diagnosis. White children were nearly 30% more likely than African-American children and 90% more likely than Hispanic children to be referred to an early-intervention program. By the end of the study, those differences had disappeared.
"For a long time, it's been felt that minority children were out there at equal rates but we just weren't doing a good job of finding those children," Landa says.
The fact that rate of early diagnoses equalized by the end of the study, she says, suggests that outreach programs to minority communities are working.
Indeed, researchers say, all groups appear to be benefiting from greater public health efforts.
"The fact that we're getting them in early is great, because the earlier we can identify children and get them enrolled in appropriate services, the better the chances are to optimize their developmental and educational outcomes," Manning says.
Manning, S. Pediatrics, online, May 16, 2011.
Robins, D. Journal of Autism and Development Disorders, 2001.
Rebecca Landa, PhD, director, Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore.
Susan E. Manning, MD, MPH, epidemiologist, CDC; Massachusetts Department of Public Health.