O aumento de casos - Outro dos misterios do Autismo

Another autism mystery: The rise in cases
Awareness and detection have grown over the years, but is that the whole story? It’s an issue made timely by insurance debate
By Marshall Allen

Fri, Feb 20, 2009 (2 a.m.)

The disorders are difficult to identify in children because there is no biological test to confirm their presence. Thus, “autism spectrum disorders” emerge as an ominous specter during early childhood years. An autistic child may respond to the sound of a refrigerator, but not his mother’s voice. He may stare off into space, but never make eye contact with his sister. His senses may by hypersensitive, to the degree that he throws tantrums around bright lights or loud noises.

Identifying the disorders is complicated by the fact that they share characteristics — often causing an impairment in socialization — but don’t share the level of severity. A child with Asperger syndrome may look and sound normal but be unable to recognize social cues, while a severely autistic child may be totally unable to speak.

In hindsight, the signs are clear. But in the course of discovering the problems they are muddled. It can take years before parents realize a child has an autism-related developmental disorder, though experts say it can be reliably diagnosed by age 3.

Once the disorder is diagnosed, early intervention is essential to ensure a child’s development isn’t stunted. Usually this takes the form of occupational and speech therapy that may cost parents tens of thousands of dollars a year out of pocket.

Democrats in the Nevada Assembly introduced a bill this week that would require insurance companies to cover the cost of therapy. Similar legislation has passed in other states. Insurance companies complain that providing autism coverage would increase premiums, which may prompt some employers to stop providing insurance.

Autism spectrum disorders have received increased national attention as their diagnosis has increased. When autism was first described, in 1943, it was assumed that it was a low-incidence disorder, and initial studies in the 1960s suggested the disorders affected perhaps five in 10,000 children, said Catherine Rice, an epidemiologist and behavioral scientist at the National Center on Birth Defects and Disabilities.

In the early years, however, only severely impaired children were placed in the autism spectrum. As researchers have learned more about the diseases, they have broadened the definition of what qualifies as an autism spectrum disorder — and today studies suggest about one in 150 children have some type of autism spectrum disorder.

So are there more autistic children, or is the broadening definition causing more children to be classified as autistic?

It’s impossible to say for sure, Rice said. Awareness of autism is increasing, which leads to more effective identification, but it’s also possible that it’s increasing. Even with the more inclusive definition, the number of autistic children seems to be on the rise, Rice said.

It’s not known what causes autism. Many autism activists claim that childhood vaccines are a factor, but Rice said there have been no studies linking the two.

Researchers say environmental factors could contribute to the onset of the disorders. Studies have linked autism to air pollutants, pesticides, pet medications and even drugs used in the birthing process, such as Pitosin, Rice said.

“It could be anything from the exposures in our physical surroundings — chemicals around us in homes, clothes, products, medications we take and food we eat,” Rice said.

Rice said the recognition that environmental factors play a role in causing autism shows that there is common ground in the debate about whether vaccines play a role in the disorders.

“The debate has been more polarizing than it is in reality,” Rice said. “Hopefully there is common ground in recognizing that autism is more complex. It’s not going to be solely explained by biology or genetics or a single environmental cause.”

Editor's note: This article has been changed to clarify the CDC's position that research has not proven a link between autism and vaccines.