What Causes Autism? Is There an Autism Epidemic in the US?

Advocacy group Autism Speaks says: “Autism is now officially becoming an epidemic in the United States. We are dealing with a national emergency that is in need of a national plan.”

When figures a few years ago showed that as many as one child in 110 in the United States had autism, leading autism research advocates called for health officials to declare a new “national emergency” and an “epidemic” that needed urgent attention.

Today, the situation is even more dire: One out of 88 children is believed to have autism or a related disorder, according to health officials who said on March 29 that autism appears to be on the rise, with the rate rising 23 percent in two years.

But officials admit they aren’t sure what’s causing the recorded rise — if it’s “real,” reflecting an actual rise in the disorder, or due in part to better recognition of cases, because of wider screening and better diagnosis. As the search for the cause of autism is really only beginning, officials acknowledge that the extent that factor influences the overall number is unknown — and other factors may be at play. It may be a mixture of both of both factors, and scientists are now examining environmental toxins, medications, nutrition and other factors as possible contributors.

“There is the possibility that the increase in identification is entirely the result of better detection. We don’t know whether or not that is the case but it is a possibility,” says Dr. Thomas Frieden, director of the Centers for Disease Control and Prevention, the agency that released the estimate.

“One thing the data tells us with certainty — there are many children and families who need help,” Dr. Freiden says. “What we do know for certain is autism is common and needs to be effectively served,” he told reporters.

The exact CDC figures

The new CDC analysis comes from the Autism and Developmental Disabilities Monitoring Network, which currently operates in 14 states: Alabama, Arizona, Arkansas, Colorado, Florida, Georgia, Maryland, Missouri, North Carolina, Pennsylvania, South Carolina, Utah and Wisconsin.

To find out if a child has autism or a related disorder, “clinician reviewers” examined the medical and school records of 8-year-olds in those states and also conducted screening to see which children met the criteria for autism, even if they hadn’t been formally diagnosed. They looked particularly at 8-year-old children because most autism is diagnosed by that age. Then, the researchers calculated how common autism was in each place and overall.

The CDC identified 3,820 children with some form of autism, out of a total of 337,093 in the surveillance areas. Analysis of the records showed that:

• For every 1,000 eight-year-old children, 11.3 had been identified as having an Autism spectrum disorder (ASD).
• That marks a 23 percent rise over the last data from two years earlier — and a 78 percent rise over the total number of cases presumed in 2002. At that time, the accepted estimate was that one in 150 children had some form of autism.
• The numbers are higher for boys, with one in 54 8-year-olds now considered to have autism, Asperger’s or a related condition.
• That means ASD is nearly five times more common in boys than girls, since the figures for girls show one in 252 had some form of the disorder.
• Previously, the disorder was believed to be more common in boys than girls by a factor of four to one.
• The rate for white children was 1 in 83, compared with 1 in 127 for Latinos and 1 in 98 for African Americans — but the data show those minorities have been closing the gap.
• In fact, the largest increases in autism prevalence were found among black and Hispanic children.
• ASD rates varied widely in the report — from one in 47 children in the western state of Utah to one in 210 children in the southeastern state of Alabama.