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| 4/23/2010 11:43:00 AM | Email this article • Print this article | Autism debate focuses on question of epidemic
Global pandemic, or myth?
Second in a series
Children who are diagnosed with autism are described as being "on the spectrum," sitting along the range of neurological impairments, from mild to severe, that compose autism spectrum disorders, or ASDs, but it could be said those so diagnosed are not the only ones on an autism spectrum.
In the politically-tinted scientific world, there is what might be called a spectrum of causality, a sweep of beliefs about autism yielding two opposing viewpoints - those who believe the globe is engulfed in an autism pandemic constituting a major public health crisis, and those scientists who say it is all a myth.
Put UW-Madison Dr. Morton Anne Gernsbacher in the latter group.
"If you have learned anything about autism lately from the popular media, you most likely have learned - erroneously - that there is 'a mysterious upsurge' in the prevalence of autism (citations omitted), creating a 'baffling . . . outbreak,' in which new cases are 'exploding in number' and 'no one knows why,'" Gernsbacher wrote in a 2005 paper, Three Reasons Not to Believe in an Autism Epidemic. "However, no sound scientific evidence indicates that the increase in the number of diagnosed cases of autism arises from anything other than intentionally broadened diagnostic criteria, coupled with deliberately greater public awareness and conscientiously improved case finding."
Put Dr. Bernadine Healey, the past director of the National Institutes of Health, in the former grouping.
"I think one has to listen to the families of these children," Healey said on Larry King Live in April 2009. "I have always believed, you listen to the patients and the patients will teach. I think there are many legitimate concerns that families have. And I honestly believe that the focus that we have on autism today and the embarrassing recognition that we know so little about it, in terms of what causes it, in terms of how to treat it, in terms of whether it's dynamic, whether it's structural, I think that says that we have neglected this disease for all too long in the face of this growing epidemic."
Certainly no one disputes the exponential rise in autism diagnoses.
Into the 1980s, no more than 5 per 10,000 persons received an autism determination. In 2006, approximately 1 percent of the child population received such a verdict, or one child in every 110.
What's disputed are the reasons for the rising rates.
Those who debunk the idea of an epidemic say they are easily explained by three reasons: Changes in diagnostic criteria for autism, with current criteria including milder forms of the disorder, such as Asperger's Syndrome, which weren't previously counted; greater awareness among both the general public and the medical community, leading to greater identification; and earlier diagnosis stemming from heightened observation.
Those who believe the epidemic is real have marshaled their own evidence.
They say common sense, on-the-ground reporting by parents prove the increase is real, no matter what the overall body of research asserts. They also attack both the methodology and conclusions of many studies, and point to pharmaceutical-backed researchers as the driving force against the idea of an epidemic.
Not least, their own comprehensive studies show, changes in diagnostic methods cannot account for anywhere near the increase, and they say rises in diagnostic rates just as easily parallel an increasing assault on children's immune systems by both environmental pollutants and medically rendered immunizations as they do changes in medical technique.
The outcome of the debate is critical, for it will affect billions of dollars of funding, which now flow primarily to researching the genetic foundations of ASD. If there is no real increase in the incidence of autism, that funding line will remain stable.
But the apple cart would be upset if autism is on the increase absolutely, for it would mean something other than genetics - something in the environment - is triggering the rise, and that funding needs to be shifted toward finding those environmental causes.
Moreover, if that something in the environment turns out to be at least partially due to the immunization schedules of young children, as many advocates in the autism community believe, billions of dollars in pharmaceutical profits could be at stake as well.
The case against an epidemic
Within the medical establishment, there's far more literature dismissing the idea of an epidemic than there is supporting it. Thus, those who give credence to the great weight of scientific thinking at any given moment can move on, for the great weight asserts, with an abundance of charts and graphs, there is no epidemic.
In 2006, for example, another Wisconsin researcher, Dr. Paul Shattuck, produced a study showing the rise in cases to be a function of what is called diagnostic substitution.
In the study, The Contribution of Diagnostic Substitution to the Growing Administrative Prevalence of Autism in US Special Education, Shattuck compared the rise in autism diagnoses with the decline of other special education diagnoses and found a strong correlation.
In other words, symptoms now categorized as autism were not so classified 25 years ago but were typed as various learning disabilities - what Shattuck called administrative prevalence.
The average administrative prevalence of autism among children increased from 0.6 to 3.1 per 1,000 from 1994 to 2003, the study found, while during the same period the prevalence of mental retardation and learning disabilities declined by 2.8 and 8.3 per 1,000, respectively.
"Higher autism prevalence was significantly associated with corresponding declines in the prevalence of mental retardation and learning disabilities," Shattuck wrote.
The declining prevalence of mental retardation and learning disabilities from 1994 to 2003 represented a significant downward trend from their trajectories of prevalence between 1984 to 1993, he observed.
"Prevalence findings from special education data do not support the claim of an autism epidemic because the administrative prevalence figures for most states are well below epidemiological estimates," he wrote. "The growing administrative prevalence of autism from 1994 to 2003 was associated with corresponding declines in the usage of other diagnostic categories."
In other words, a child who might have been called retarded in 1984 or 1993 could well be labeled autistic today.
A more recent 2008 British study at the University of Oxford supports Shattuck's claim. In that study, researchers suggested, many children diagnosed with severe language disorders in the 1980s and 1990s would today be diagnosed as having autism.
Professor Dorothy Bishop led a study that revisited 38 adults, aged between 15-31, who had been diagnosed with having developmental language disorders as children rather than being autistic.
Bishop and her colleagues said they looked at whether those adults now met current diagnostic criteria for autistic spectrum disorders, either through reports of their childhood behavior or on the basis of their current behavior.
Of the 38 adults, eight now met the criteria for autism, and four more met criteria for milder forms of ASD.
Accordingly, at least 21 percent of the group would today receive an ASD diagnosis.
"Our study shows pretty direct evidence to support the theory that changes in diagnosis may contribute towards the rise in autism," Bishop said when announcing the results. "These were children that people were saying were not autistic in the 1980s, but when we talk to their parents now about what they were like as children, it's clear that they would be classified as autistic now."
Other researchers - namely, Ka-Yuet Liu, Marissa King, and Peter S. Bearman of Columbia University - say awareness and social influence play a major role.
"Using California data, (our) study shows that children living very close to a child previously diagnosed with autism are more likely to be diagnosed with autism," they wrote. "An underlying social influence mechanism involving information diffusion drives this result, contributing to 16 percent of the increase in prevalence over 2000-2005."
Loosening the criteria
The criteria for diagnosing autism is far broader and casts a much wider net than it did in 1990, a fact underlying the notion of diagnostic substitution.
"One thing that some people fail to realize is there were no standard diagnostic criteria for autism in the Diagnostic and Statistical Manual (of the American Psychiatric Association), the DSM, until 1980, and the criteria in the DSM have undergone purposeful change during the past 25 years," Gernsbacher said in an interview with Medscape in 2005. "Therefore, any estimates of the prevalence of autism prior to 1980 would have been based on individual clinicians' or specific researchers' definitions, and would have fluctuated because of factors that continue to introduce variation into current-day estimates, such as variation in the size of the population sampled and the manner of identification. Estimates since 1980 would have been based on changing versions of the DSM criteria."
For example, she stated, the 1980 DSM-III entry required satisfying six mandatory criteria, while the 1994 DSM-IV offered 16 optional criteria, only half of which needed to be met. In addition the DSM-III comprised only two diagnostic categories; the DSM-IV, five.
What's more, she said, the criteria were themselves more rigorous. In 1980, an individual needed to exhibit a pervasive lack of responsiveness to other people, for example, while after 1994 an individual only had to demonstrate a lack of spontaneous seeking to share.... achievements with other people to be labeled autistic.
The bottom line is, at least for these researchers, there is no increase in autism and certainly no autism epidemics.
The case for an epidemic
Those who believe a full-blown pandemic is underway are not swayed by the daily dose of studies and interviews designed to dismiss what they call the reality of a crisis quickly reaching a critical point.
For one thing, they say, anecdotal reporting from the field contradicts findings of no real increases. Talk to teachers, health workers, and parents, they say, and these people are convinced they are seeing more distinctively autistic children than in the past.
In their book, Healing and Preventing Autism, Jenny McCarthy and autism expert Dr. Jerry Kartzinel say pediatricians most often resist autism diagnoses, even as parents point out the symptoms.
If there was a rush to diagnostic substitution, the opposite would be true.
"Also, I would like to mention that until recently an autism diagnosis usually came from the mother-in-law, the speech therapist, the school nurse or the next-door neighbor - anybody but the pediatrician, which I always thought was funny," Kartzinel said in the book.
McCarthy, too, cites parents with reports of pediatricians attempting to talk them out of referral to a diagnostic clinic, saying the child would soon "catch up to the other children."
So the anecdotal evidence does not support diagnostic substitution but rather a resistance to it within the medical establishment, and that would have been especially true in the mid-1990s, when the caseloads began to grow rapidly.
But those who say an epidemic is real have a lot more than anecdotal evidence on their side.
For one thing, they take issue with many of the studies and with researchers themselves, some of whom they say are funded by pharmaceutical companies looking to protect vaccination revenues.
For example, Bishop's research was funded by the Wellcome Trust, which was founded by the American-born pharmaceutical magnate Sir Henry Wellcome and which for years held stock in the pharmaceutical giant GlaxoSmithKline and its predecessor. Though the foundation has divested itself of its holding in the company, it continues to participate in major collaborations with GlaxoSmithKline.
Gernsbacher has also been criticized. For one thing, Gernsbacher, who has an autistic son and hails from a branch of psychology known as neurodiversity, doesn't believe autism is a disorder at all.
To call for its eradication, she wrote in a 2004 Wisconsin State Journal column entitled "Autistics need acceptance, not cure," is to call for the eradication of those with autism.
"(My son) understands quite well that there are so-called autism 'advocates' who despise autism, who march thousand-fold against it with placards calling for its defeat, its demise. His demise," she wrote. ". . . History suggests that many individuals whom we would today diagnose as autistic - some severely so - contributed profoundly to our art, our math, our science, and our literature. Most poignantly, many autistics affirm that it would be impossible to segregate the part of them that is autistic. To take away their autism is to take away their personhood."
Gernsbacher's portrait of autism as a natural and special - she used the word 'precocious' - genetic condition doesn't allow for a rapidly rising increase in its incidence, which would concede an environmental component and betray its character as unnatural, as a disorder.
Through the years she has received funding from the National Institutes of Health, the Army Research Institute, and the Air Force Office of Sponsored Research, as well as the Centers for Disease Control.
The Army Research Institute has long collaborated with pharmaceutical companies, and the Centers for Disease Control has come under fire from Robert F. Kennedy Jr. and others for its relationship to the drug industry, particularly on the issue of autism.
After the CDC published a study in 2003 repudiating any possible link between thimerosal and developmental problems such as autism, documents obtained through the Freedom of Information Act showed the CDC had held meetings prior to undertaking the study with both the FDA and representatives from the vaccine industry.
As Kennedy related it in 2005 in Salon.com, "The federal officials and industry representatives had assembled to discuss a disturbing new study that raised alarming questions about the safety of a host of common childhood vaccines administered to infants and young children. According to a CDC epidemiologist named Tom Verstraeten, who had analyzed the agency's massive database containing the medical records of 100,000 children, a mercury-based preservative in the vaccines - thimerosal - appeared to be responsible for a dramatic increase in autism and a host of other neurological disorders among children."
The CDC subsequently paid the Institute of Medicine to conduct a new study to whitewash the risks and "ordered" researchers to "rule out" the chemical's link to autism, Kennedy wrote.
Kennedy continued assailing the CDC in 2009.
"Even as the evidence connecting America's autism epidemic to vaccines mounts, dead-enders at the Centers for Disease Control (CDC) - many of whom promoted the current vaccine schedule and others with strong ties to the vaccine industry - are trying to delay the day of reckoning by creating questionable studies designed to discredit any potential vaccine-autism link and by derailing authentic studies," Kennedy and David Kirby wrote in a Huffington Post piece called "Autism, Vaccines and the CDC: The Wrong of Side of History."
Deficient research
Researchers aside, those who believe that diagnostic and administrative manipulation cannot explain away the rising number of cases point to the flawed methodology of the studies themselves.
For example, Bishop's study demonstrating diagnostic substitution was based only on a review of the records of 38 subjects, far too small a sample to be scientifically valid, critics say. What's more, only 21 percent of the group would have been diagnosed as autistic today, a percentage shift too small to account for the magnitude of the increase in autism diagnoses.
Other numbers do not support studies showing diagnostic substitution, either.
Shattuck's research, for instance, points to the declining prevalence of mental retardation and learning disabilities from 1994 to 2003, at a time when autism diagnoses were rising, as evidence of diagnostic substitution.
Interestingly, though, in 1982, there were 1.7 million learning disabled, 1.1 million speech impaired, 780,000 mentally retarded and 353,000 emotionally disturbed. According to figures released by the U.S. Department of Education in 1991, the growth of the number of children in the learning disabled category had jumped 9 percent between 1982 and 1985, and by 32 percent since 1985, to about 2.44 million.
In 1998, four years after the new DSM-IV and the spike in autism diagnoses, the learning disability category was still growing significantly, reaching 2.7 million. By 2003, the learning disabled category stood at 2,866,908.
That suggests little diagnostic substitution, at least from the learning disabled category, and a factual finding at odds with Shattuck's statistics on learning disabilities.
There was a significant decline among the mentally retarded - from 780,000 in 1982 to 602,000 in 1998, as Shattuck observed in his findings, but that number stabilized and declined only insignificantly between 1998 and 2003, to 582,663, while autism diagnoses were still growing at an astonishing rate. While Shattuck bases his substitution theory on declining retardation diagnoses between 1994 and 2003, a fair reading shows most of the decline occurred by 1998, with almost no decline for the five years preceding 2003.
Thus, diagnostic substitution of autism for mental retardation would not seem to have been possible between 1998 and 2003.
Dr, Craig Newschaffer of Drexel University also took issue with Shattuck's study, which used estimates of percent changes in autism classification prevalence compared with absolute changes in the prevalences of other classifications.
That, Newschaffer wrote in 2006, made it difficult to determine whether there was, overall, the potential for offset as demonstrated by "equal-magnitude, opposite-direction" changes.
"In the end, we may have to live with the fact that although administrative data suggest the potential for some diagnostic substitution, it remains difficult to confidently ascribe all of the observed autism prevalence increase to this particular phenomenon," he wrote. "I also believe that the time has come to accept that, given the behavioral basis of the autism diagnosis, the lack of knowledge about autism's underlying etiology, and the limitations of retrospective analyses, we are not likely to develop a conclusive body of evidence to either fully support or fully refute the notion that there has been some real increase in autism risk over the past 2 decades."
Not only that, but if diagnostic substitution had occurred, and there were as many autistic people in the early 1990s as today, many people have obvious disappeared, says J.B. Handley, the cofounder of Generation Rescue.
"I want to talk about this issue of autism prevalence," Handley said on Larry King last April. "It's going to be shocking for parents to learn that the CDC and the AAP don't actually acknowledge that there's been a real rise in autism cases. Larry, the Department of Education in 1992, 16,000 kids were getting autism services. Today 225,000. That means in 1992, they were missing 93 percent of kids with autism. Where are all the adults with autism? They don't exist."
Others have compared the rise in autism rates with those of childhood asthma, which have also skyrocketed. Then, as in autism now, they say, medical officials originally ascribed the increase to better reporting, though that notion has been abandoned.
New study
Finally, a 2009 University of California study contends the rise in autism diagnoses cannot be attributed to diagnostic substitution, and that a real epidemic is underway.
UC-Davis researchers found that the seven- to eight-fold increase in the number of children born in California with autism since 1990 could not be explained by either changes in how the condition is diagnosed or counted - and the trend shows no sign of abating, the university stated in announcing the study.
Published in the January 2009 issue of the journal Epidemiology, the study suggested shifting research resources from genetics to environmental chemicals and infectious microbes that could be the root cause of the problem.
"It's time to start looking for the environmental culprits responsible for the remarkable increase in the rate of autism in California," said UC-Davis lead researcher Irva Hertz-Picciotto, a professor of environmental and occupational health and epidemiology.
According to the study, the incidence of autism by age six in California increased from fewer than nine in 10,000 for children born in 1990 to more than 44 in 10,000 for children born in 2000.
Hertz-Picciotto and co-author Lora Delwiche of the UC-Davis Department of Public Health Sciences analyzed data collected by the state of California Department of Developmental Services (DDS) from 1990 to 2006, as well as the United States Census Bureau and state of California Department of Public Health Office of Vital Records, which compiles and maintains birth statistics.
The two correlated the number of autism cases reported between 1990 and 2006 with birth records and excluded children not born in California. They used Census Bureau data to calculate the rate of incidence in the population over time and examined the age at diagnosis of all children ages two to 10 years old.
The methodology eliminated migration as a potential cause of the increase in the number of cases, the researchers stated, and it further revealed that no more than 56 percent of the estimated 600-to-700 percent increase - less than one-tenth of the increased number of reported cases - could be attributed to the inclusion of milder cases of autism, while only 24 percent of the increase could be attributed to earlier age at diagnosis.
"These are fairly small percentages compared to the size of the increase that we've seen in the state," Hertz-Picciotto said in a statement.
Hertz-Picciotto said the study was a clarion call to researchers and policy makers who have focused attention and money on understanding the genetic components of autism, and she said the rise in cases could not be attributed to the state's diverse population because the disorder affected ethnic groups at fairly similar rates.
"Right now, about 10 to 20 times more research dollars are spent on studies of the genetic causes of autism than on environmental ones," she said. "We need to even out the funding."
Hertz-Picciotto and her colleagues at the M.I.N.D Institute are currently conducting two large studies aimed at discovering the causes of autism.
"We're looking at the possible effects of metals, pesticides and infectious agents on neurodevelopment," Hertz-Picciotto said. "If we're going to stop the rise in autism in California, we need to keep these studies going and expand them to the extent possible."
The next article in this series looks at the potential causes of autism, and explores the debate over vaccines and autism.
Richard Moore can be reached at rmmoore1@verizon.net.
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Reader Comments
Posted: Monday, April 26, 2010
Article comment by:
Stan
Now that's what I call an "investigative reporter". You do the term credit, Mr. Moore. Can't say that for many reporters, these days.
In your next article, on causation, I hope you follow such leads as how the Powers-That-Be muddied the waters by not only changing the criteria ("diagnostic substitution"), but adding the thimerosal-bearing flu shot to the vax schedule as they phased it out of other shots, and tried to use that phase-out as proof that it made no difference to the incidence of ASD. Recommending a mercury-containing vax to pregnant women has to be one of the most gratuitous insults to common sense in this whole sordid saga. Another poster has pointed out the potential role of amalgam fillings in this time period. Please also check, from non-industry sources, any research on the incidences of ASD amongst women given either the rho-Gam or the flu shot(s) during pregnancy. And keep up the excellent work.
Posted: Monday, April 26, 2010
Article comment by:
Frank Cummins
"...the decrease in mentally retarded is likely due to selective abortion from amniocentisis results."
Unlikely. That only applies to Down Syndrome. If you define MR as IQ<70, then 2.3% of the US population is MR. Down is a small percentage of that number, possibly less than 6%.
Posted: Monday, April 26, 2010
Article comment by:
Jenny M Webster
For those of you who still cling to that ignorant notion (broadening of diagnostic criteria), brace yourselves. Our children will be adults soon. The schools will no longer be responsible for them during the days, most of us are single parents... so either we will all have to quit our jobs and go on welfare OR place our kids into institutions.
--either way, the cost will be immense. Think you pay a lot of taxes now?
I laugh at your ignorance. Maybe the "I don't care b/c it doesn't involve me" crowd should start listening to us parents when we tell you WHAT WORKS to make our kids better. Investing in these kids when they are young will save us ALL money in the long run.
You are in for a rude awakening.
Posted: Sunday, April 25, 2010
Article comment by:
Ralph Westin
Thank you for quoting Dr. Jenny McCarthy. She is a very bright and learned woman, and parents could do no better than to listen to her sound medical advice.
Posted: Sunday, April 25, 2010
Article comment by:
Robin P Clarke
A most commendable article. Halfway through it looked like the anti-increase lobby were going to win the day! I reserve from saying excellent only due to the lack of mention of the unchallenged theory http://cogprints.org/5207, of which the update (submitted for publication) decisively explains the increase as due to the introduction of non-gamma-2 dental amalgams in the 1970s, re which see www.autismcauses.info www.autismcauses.info.
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