Ped Med: Debate mounts over autism counts

SAN FRANCISCO, Oct. 5, 2006 (UPI) -- Even as new numbers are reported of autism diagnoses in America's children, the sum total of their meaning remains embroiled in controversy.

So much so, divisions are being drawn even between parties with a shared personal interest in the outcome.

As a case in point, when investigators at the University of California, Davis, M.I.N.D. Institute declared an unprecedented increase in the most populous state's autism rates is real and cannot be explained away by such factors as misclassification and diagnostic criteria changes, another group of respected scholars challenged the findings and offered "three reasons not to believe in an autism epidemic."

What made the dichotomy all the more striking is that, while such divergent views abound, both of these positions came from parent-powered perspectives.

The M.I.N.D. Institute was co-founded by a group of moms and dads with autistic children, a feature shared by two of the authors of the competing study. The third is autistic herself.

Even though it was not published in a peer-reviewed journal -- typically a key criterion for establishing a study's credibility -- the M.I.N.D. survey, led by UC Davis pediatric epidemiologist Robert Byrd, has been widely viewed and cited as incontrovertible evidence of an epidemic.

It holds such sway in part because whereas accurate counts generally are hard to come by, California mandates special services for all children diagnosed with autism and other developmental disorders, and, thus, requires separate recordkeeping of such cases.

Considered to have the best autism reporting system in the United States, California is generally viewed as a bellwether for the rest of the nation -- and as the great numerical hope that can settle the controversy over whether any connection exists between autism and vaccines.

If the most accurate record of trends in autism shows the numbers are declining alongside the removal of thimerosal from childhood shots, it would give a sizeable boost to the theory that hangs on rates of the disorder rising and falling with the extent of youngsters' exposure to the mercury-based preservative.

Because thimerosal was removed from vaccines starting in 1999-2000 and the last of the unexpired shots were expected to have run out of shelf life by the end of 2002, by the time babies born around that date turn 5, the mercury-autism-theory proponents expect to have a pretty convincing picture of the thimerosal effect.

Many are betting on the autism rates starting to slip sometime around late 2006, early 2007.

The M.I.N.D. study was commissioned by California's legislature and governor to explain a startling 273-percent jump observed between 1987 and 1998 by the Department of Developmental Services in the number of autistic children entering the state's 21 regional service centers.

"Autism, once a rare disorder, is now more prevalent than childhood cancer, diabetes and Down syndrome," the department noted in a subsequent report.

In a mere four years the number of individuals with autism served statewide ballooned from 10,360 in December 1998 to 20,377 in December 2002, it said.

The M.I.N.D. investigators failed to uncover the reasons for the surge but deemed it an authentic representation of rising autism rates and not a reflection of any outside factors.

But some other researchers, including a group relying on the same California reporting system, begged to differ.

Of 4,590,333 babies born in the state between 1987 and 1994, 5,038 were diagnosed with autism and 11,114 with mental retardation without autism, these doubting Thomases noted.

Over the eight birth years the rate of autism for children enrolled in special education rose from 5.8 to 14.9 per 10,000. At the same time, the retardation rate fell from 28.8 to 19.5 per 10,000.

To the authors, these figures -- which suggest that perhaps children once considered retarded are now placed in the autism category -- make a good argument for crediting improved detection and changed diagnostic practices for much of the increase in autism caseloads.

For one, these researchers say, doctors now recognize that, contrary to previously held notions, the disorder can exist among individuals at every level of intelligence -- not just in those with mental retardation.

"The one thing that our center likes to talk about is what we call the changing numbers," said Dr. Rafael Castro of the Children's Evaluation Center in Boston, who was not involved in the report.

"At one point ... three-quarters of our children were considered to fall in the additional category of mental retardation," he added. "Nowadays, those numbers have been formally revised downwardly to 50 to 55 percent."

As diagnostic methods are further refined and more rigorous studies conducted, he expects those numbers to fall even more.

Part of the rate reversal also may be due to a societal shift in attitudes that, in contrast to previous decades, now attach more stigma to mental retardation than to autism, conjectures Bryna Siegel, professor of psychiatry at UC San Francisco and director of the Autism Clinic at the affiliated Langley Porter Psychiatric Institute. She has been treating autistic children for more than 30 years.

It may be physicians in the 1980s found it "easier" to tell parents a child was mentally retarded than autistic, but now the reverse is true, she speculated.

Or it may be that until recently, "it probably behooved parents to get their kids a diagnosis of mental retardation rather than autism, because at least the mental retardation system in most states, while relatively parochial or paternalistic in its approach, offers some kind of lifelong care for children," proposed David Mandell, assistant professor of psychiatry at the University of Pennsylvania School of Medicine in Philadelphia.

Morton Ann Gernsbacher, Michelle Dawson and H. Hill Goldsmith cite a host of other suspected reasons for the numerical shifts -- and for taking issue with the M.I.N.D. study's conclusions.

Gernsbacher is president of the Association for Psychological Science, a non-profit group representing 14,000 scientists, academics, clinicians, researchers, teachers and administrators, and Vilas Research Professor and Sir Frederic Bartlett Professor at the University of Wisconsin in Madison, where Goldsmith serves as UW Foundation Fluno Bascom Professor and Leona Tyler Professor.

They are parents of a child with autism. Dawson, who is autistic herself, holds the post of research associate at the Pervasive Developmental Disorders Specialized Clinic at the University of Montréal in Canada.

"According to some lay groups, the nation is experiencing an autism epidemic -- a rapid escalation in the prevalence of autism for unknown reasons," the authors write.

"However, no sound scientific evidence indicates that the increasing number of diagnosed cases of autism arises from anything other than purposely broadened diagnostic criteria, coupled with deliberately greater public awareness and intentionally improved case finding."

As we will see, the critics take issue with all of these arguments.

Next: Looking at autism's history

--

UPI Consumer Health welcomes comments on this column. E-mail: lwasowicz@upi.com

Copyright 2006 by United Press International. All Rights Reserved.