Better detection, parental factors could explain surge
Two weeks ago federal officials reported that autism cases are on the rise again. Unfortunately, the rate has grown to about 1 in 88 children throughout the United States, up from the previous estimate of 1 in 110.
The Centers for Disease Control and Prevention report containing the data showed that the largest increases over time were among Black and Hispanic children. Researchers said they suspected that some of this could be explained by better screening and diagnosis. “However, this finding explains only part of the increase over time, as more children were identified in all racial and ethnic groups,” the report said.
New research is focusing national attention on the need for earlier diagnosis and treatment, especially in rural and minority communities.
Figures released in late March by the Centers for Disease Control and Prevention has shown a 23 percent increase in autism spectrum cases from 2006 to 2008, and 78 percent increase since 2002.
For decades now, Black and Hispanic children have lagged behind whites in previous counts. Numbers are higher for boys, with one in 54 8-year-olds now considered to have autism, Asperger’s or a related condition, though no one knows why the condition is five times more likely to affect boys than girls.
The prevalence of the condition has risen nearly 80 percent over the past decade, federal health officials reported.
The survey, sponsored by the Centers for Disease Control and Prevention, is the latest evidence of a steady upward trend in a disorder whose cause remains unknown despite much research in recent years.
The rising rate of autism could be the result of finding children missed in earlier surveys or an actual increase in the condition — or a combination of the two. The trend has been observed in Canada and Western Europe as well as the United States.
In the past week, a spate of studies released during National Autism Awareness Month has offered tantalizing new information about potential causes. Research published in the journal Nature widened the understanding of the genetic roots of some cases and confirmed the elevated risks for children with older fathers. Another study, released online Monday in Pediatrics, suggested maternal obesity may play a role.
To be sure, finding the causes of autism — an umbrella term for a variety of disorders that delay children socially or intellectually — remains daunting. The causes are believed to be complicated, and not necessarily the same for each child. Some liken autism to cancer — a small word for a wide range of illnesses. In many cases, autism can be blamed on both genetic problems that load the gun and other factors that pull the trigger.
Children with the most extreme form of autism are socially withdrawn, speak little, dislike affection and eye contact, and engage in repetitive actions. Once thought to be very rare, milder forms are now recognized. One of them, Asperger syndrome, describes behavior that in the past might have been seen as peculiar and abnormal — but not evidence of illness.
The CDC study surveyed 14 states for the prevalence of autism-spectrum disorders among 8-year-olds in 2008. The prevalence that year of 11.3 cases per 1,000 children was 23 percent higher than in 2006. It was 78 percent higher than in 2002, when the survey began. Autistic children received their diagnosis at age 4 on average — six months earlier than in 2006, but not early enough for optimal therapy, according to many experts.
The survey found large unexplained differences between sexes, among ethnic groups and in states.
The fraction of autistic children with average or above-average intelligence has risen more than the fraction with “intellectual disability.” Autism prevalence in Hispanic children is two-thirds that of white children, but it is rising faster in them and in Black children than in white ones.
“This is the billion-dollar question, isn’t it?” said Li-Ching Lee, an epidemiologist who headed the survey in Maryland.
In a telephone briefing with reporters, Thomas R. Frieden, CDC’s director, said the increase could be “the result of better detection. It is a possibility.”
What’s not a matter of debate, he said, is that autism is more common and that doctors and teachers need to diagnose children earlier, when treatment is most effective.
“There are many children and families who need help. There are many children who are not receiving services early enough, or consistently enough,” Frieden said.
Autism often has devastating effects on families, and treatment requires time, skill and extreme patience. Medical expenses for children with autism are six times as high as those for children without the disorder. Behavioral therapy, often delivered one-on-one, can cost as much as $60,000 per year. The advocacy group Autism Speaks estimates autism spectrum disorders costs the United States $137 billion a year.
Most parents of autistic children — and their advocacy organizations — strongly dispute the idea that a looser definition of autism and more assiduous search for mild cases explains the trend.
“Autism is now officially becoming an epidemic in the United States. We are dealing with a national emergency that needs a national plan,” Mark Roithmayr, president of Autism Speaks, said to The Washington Post.
“Only part of the increase is better diagnosis. Something is going on here that we don’t know,” Roithmayr said. He added that “we desperately need deeper and broader funding” for treatment of the disorder and research on its causes.
CDC has several studies underway assessing genetic, reproductive, environmental and behavioral variables associated with autism. One of them, the Study to Explore Early Development (SEED), is following 2,700 children and their families in seven states.
“These stunning new figures are a call to action among our elected leaders to minimize our children’s exposures to mercury and other toxic chemicals,” said Ken Cook of Environmental Working Group. “Upending the federal government’s approach to regulating toxic chemicals and putting tough emissions standards in place at power plants are two good places to start.”
Research suggests that some families have a genetic predisposition for autism and that parental age may play a role. There’s also evidence the condition may begin before birth and be the end result of a disordered process of brain development. A recent study in mice showed that an autism-like disorder could be reversed by bone-marrow transplantation that restored a certain type of cell, called microglia, to the brain.
In the CDC study, surveyors looked for 8-year-olds who were getting special education services or were being treated at specialty hospitals or medical units for one of three “autism-spectrum” disorders. The children’s records were then reviewed by clinical experts to see that they actually fit the diagnosis. The children themselves, however, were not examined.
Among the children with a diagnosis in their medical records, 44 percent had autistic disorder (which is at the severe end of the spectrum); 47 percent had pervasive developmental disorder; and 9 percent had Asperger syndrome. The prevalence of all three subtypes has been rising in about the same proportion, according to the survey.
Warning signs of autism
Doctors now say that autism can be detected as early as 18 months, though some of its symptoms overlap with other conditions. Parents and pediatricians should be concerned if an older infant or toddler:
• Does not follow a pointed figure or use his or her own finger to point to objects
• Acts as if deaf
• Fails to respond when his or her name is called;
• Has poor eye contact
• Rarely tries to imitate sounds and movements others make, such as smiling and laughing, during simple social exchanges;
• Infrequently seeks adult attention
• Is delayed in motor development, including delayed rolling over, pushing up and crawling.
If the rising prevalence represents an actual increase of the disorders — and is not the consequence of finding previously undiagnosed cases — that suggests there may be environmental exposure or demographic change (such as older parenthood) that is responsible, because a population’s genetic background wouldn’t change over a few decades.
“There’s the real possibility that the new definition will actually be better for children and better for families,” said Susan Hyman, chairwoman of the pediatric society’s autism subcommittee. She says autism is much better understood today than it was the last time the definition was changed in 1994.
Sources: CDC, Susan Levy, Children’s Hospital of Philadelphia; Rebecca Landa, Director of the Center for Autism and related Disorders. The Washington Post also contributed to report.
Zack Burgess is an enterprise writer for The Tribune. He is a freelance writer and editor who covers culture, politics and sports. He can be contacted at zackburgess.com.