Archive | Epidemiology RSS feed for this section

CDC conference call: 1% autism prevalence.

18 Dec

The CDC conference call was today. This call was about the new MMWR (Morbidity and Mortality Weekly Reports) that is due out. (The report is here, with an appendix here).

Dr. Catherine Rice, lead author was there. She gave the intro.

Report is released today. “Significant public health issue”. We need a coordinated and strong response to improve the lives of people with ASD.

2006–identified prevalence to be about 1% of 8 year olds. Representing about 8% of 8 year olds. 4.2 to 12.1 per 1000, average of 9.0 per 1000 (1 in 80 to 1 in 240, average on in 110)

The ADDM network collects data from multiple sites. All showed increases in identified ASD prevalence. The increases ranged from 27% to 95%, with an average of 57%

Identified ASD prevalence increased across all categories. Increases 55% for White, 90% for Hispanic (missed African American)

The autism prevalence is 4-5 times higher for boys. Prevalence numbers are 1 in 70 boys, 1 in 315 girls (average). The increases were 60% for boys, 48% for girls.

There were between 13-35% of the children studied who had a report of regression or loss of skills by age 2.

For most children, concerns were noted in the records were noted before age 2, but average identification age is about 4.5 years of age.

No single factor explains increase. Better detection is a factor (girls, Hispanics, people without cognitive impairment were given as examples of improved detection). True increase can not be ruled out.

CDC has new studies (such as SEED) to look into causes of autism. CDC is also represented on the IACC.

Some of the increase is due to better record keeping. One question from WebMD was about a possible true increase. CDC responded about the various factors involved, but a true increase can not be ruled out.

Boston Globe: (1) why are there broad “incidence” rates across sites (2) what about this study in terms of vaccinations.

Rage is 4.2 to 12.1 per 1,000. 7 sites were much more closely grouped around 10 per 1,000 (1%). There is a variation in the types of records available. The CDC representative states the low numbers are likely a low estimate.

Since autism is a behaviorally diagnosed condition, there will be variation in prevalence by region.

This study is not designed to look at risk factors, including vaccine. The children in this study were born in 1998, so these children were vaccinated with thimerosal.

NY Times: Range of spectrum. How well does this study catch the more “mild” end of the spectrum like PDD-NOS and Aspergers.

This went by fast, but it sounded like the CDC said that autism and PDD-NOS were more represented than Asperger syndrome.

CDC: The researchers do not actually test the children, but work on a review of existing records.

Pediatric news: What is the take home message for pediatricians?

CDC: Since there was usually an indication of delay before the age of 2, but identification wasn’t made until (on average) 4.5, pediatricians should be proactive in referring children for further evaluation.

In response to one question on intellectual disability: there is an overlap between autism and intellectual disability. Old stats showed 75% of autistics had Intellectual disability. Now it is more like 41%. This points to the idea that either the nature of autism is changing or that identification methods are changing, catching more autistics without intellectual disability.

CNN question–how much did the average age of diagnosis change?

CDC: 5 months. Children were identified on average 5 months sooner in these data than in the previous study.

Note: I made significant updates to this post since it was first published.

Is CDC to announce 1 in 100 autism rate?

18 Dec

And, if so, is SafeMinds trying to play games with Google news to get their story on top?

What happens when you are the first to break a big news story, at least in terms of Google News? Well, quite often your story gets to be the top story.

On Wednesday, SafeMinds put a piece on the Age of Autism Blog CDC Study Expected to Announce 1 in 100 Autism Rate—A Startling 50% Jump in Just Two Years. Evidence Points to an Environmental Trigger. Then, on Thursday, basically the same piece reappeared as CDC Brings Bad Tidings: 40,000 Children Diagnosed With Autism In This Year Alone. They open with:

Atlanta, GA – A study to be released Friday by the Autism and Developmental Disabilities Monitoring (ADDM) Network of the Centers for Disease Control (CDC) is expected to report that autism prevalence has reached the epidemic rate of 1 in 100 children.

Usually when a new study comes out, journals or the CDC will release some information to the press on the condition that they respect the “embargo”. That is, everyone is supposed to wait until the same time before going public with the information.

There are advantages to not playing by the rules. When you get your story out first, especially on a big story, you can try to influence other stories and you can ride the top of the wave of press coverage.

Take a look at Google News for a big story and often there is a “lead” or top story. No one wants to be burried in the mass of stories. Get your story out first, and, hey, maybe you will be the top story.

That would be a big public relations coup for SafeMinds. At the same time, we have to ask: if SafeMinds is correct, are they breaking an embargo? The release of information about a recent Pediatrics study claiming a 1% autism prevalence caused some bad press for the autism community (also here and here).

Let’s watch. Will SafeMinds put out yet another post Friday morning, just in case? Will they succeed in getting a prominent spot for their pieces? Will journalists covering the story contact SafeMinds or use their material for stories?

The CDC autism prevalence estimates are made via MMWR’s (Morbidity and Mortality Weekly Reports). The previous report was from 2007, using data collected in 2002, with the 1 in 150 prevalence estimate that has been commonly quoted.

If you recall, the existence of the upcoming MMWR was leaked a few months ago. Lee Grossman, president of the Autism Society of America, somehow found out and talked publicly, and David Kirby blogged it. Of course, Mr. Kirby found a way (or was told a way) to include this as evidence of vaccines causing autism. The argument being that the Hepatitis B vaccine was given to those kids. It didn’t matter that the other dataset he was discussing in that same post, from the National Children’s Health Survey, didn’t support the idea at all. SafeMinds seems to be making the same arguments in their blog pieces as well.

If SafeMinds is correct and the announcement comes out Friday, expect updates on the CDC autism data page, and the CDC autism page. But, hey, expect about 5,000 news articles too.

Bob Wright snubs autistic adults, the same group who live in poverty

23 Nov

The New York Post reported on Autism Speaks founder Bob Wright having a grumpy slap at adult autistic people who were protesting the fact that Autism Speaks still has no autistic representation on its Board.

Bob Wright had harsh words for protesters who tried to muck up the A-list benefit concert he put on at Carnegie Hall on behalf of autistic kids.

“The protesters are lucky,” said Wright. “They’re well off enough, healthy enough, to do it. I wish my grandson were able to join them.”

Wright runs Autism Speaks, which has raised over $200 million for research into a disorder that afflicts mainly children.

That didn’t stop a clutch of sign-carrying adult protesters from descending on Carnegie Hall Tuesday night, trying to disrupt a concert attended by Donald Trump, Howard Stern and Martha Stewart. Protesters complain that there’s not one autistic person on the board of the org, which produced an “offensive” ad suggesting that autism was a fate worse than death.

Wright, whose grandson cannot talk because of autism, said the disorder is exploding among young kids who can’t speak for themselves.

“This is serious business,” he said.

Note how the reporter states that the benefit was for autistic kids and further states that autism affects mainly children. This should give some insight into the silly one dimensional world that the Wrights, and by extension, Autism Speaks inhabit. Of course autism doesn’t affect mainly children. In fact, it would seem that the reverse is true.

I would like to suggest to Bobo that what is serious business is blindly misrepresenting autism either purposefully or (more likely) out of ignorance. I would also like to suggest that its about time Autism Speaks walked the walk and got aome autistic Board level members. I would further suggest that Bobo wakes up and smells the coffee. Young autistic kids definitely find it difficult to talk for themselves. Most kids of his grandsons age might find it difficult to form coherent opinions on high level concepts like the right to be who you are. In the meantime, having an autistic Board level member would be a step in the right direction. I’d happily accept Jake Crosby or Jon Mitchell. Two men who I vehemntly disagree with yet who’s opinion on autism I respect due to their diagnosis.

Maybe Bobo might take a look across the pond if his cheeks aren’t still smarting from the slapdown he got last time he came over here. Maybe the reality of life for autistic adults over here might cause him to get a bit of a reality check as to where his research priorities should lie. As he continues to steer Autism Speaks down the increasingly stupid looking anti-vaxx hypotheses,

A THIRD of Wales’ autism sufferers are unemployed and living in ‘poverty’ without benefits, a charity has said.

9,000 autistic adults are surviving (sort of) on handouts from friends and family. Not only are they subject to ignorance in job centres, they are not made aware of _how_ to make a claim:

She [Shirley Parsley] said: “It is scandalous, therefore, that thousands of people with this serious, lifelong and disabling condition are being consigned to poverty by a complex and counter-productive benefits system.”

This is the reality of life for autistic adults. Abandoned by a state system and also abandoned by Autism Speaks, an organisation focussed solely it seems on people of Bob Wright’s grandchilds age. Whilst Bobo complains about how autism is ‘exploding amongst kids who can’t talk for themselves’ (a factoid for which there’s no valid science), the adults he and his organisation turn their backs on are literally starving.

Evaluation of Immunization Rates and Safety Among Children with Inborn Errors of Metabolism

2 Nov

Ever since the Hannah Poling case became public, and especially give the way in which David Kirby has presented the case, there has been a question of whether vaccines can cause regressions in children with inborn errors of metabolism (mitochondrial disorders are a subset of these).

I discussed one very recent paper Fever Plus Mitochondrial Disease Could Be Risk Factors for Autistic Regression. Commenter and LBRB blogger Joseph made the very correct observation then:

I’d say it’s potentially interesting, but limited. In order to tell that something is a risk factor, you need a case-control study.

More specifically, can self-selection bias be discounted in this study?

It is encouraging to see that such studies into this question are being staged. Here is the abstract from a study presented 2009 Infectious Diseases Society of America titled, Evaluation of Immunization Rates and Safety Among Children with Inborn Errors of Metabolism.

Abstract

Background: Children with metabolic disorders are a potential high-risk group for vaccine-preventable diseases. Despite recommendations that they receive all routine immunizations, information regarding both immunization rates and safety data within this population is lacking.
Methods: Using Northern California Kaiser Permanente’s (NCKP) integrated electronic medical record, we identified children up to age 18 years who had an inborn error of metabolism (IEM) from 1990 to 2007. We assessed immunization rates among a subset of infants with IEM born at NCKP who were members until age 3 years matched to healthy infants (1:20), comparing both immunizations received by age 2 years and timing for receipt of vaccines. We next separately assessed for adverse events after immunization by using self-controlled analyses among all children up to age 18 years with an IEM who received at least 1 vaccine at any time, comparing emergency room visits and hospitalizations during post-vaccine days 0-30 to post-vaccine days 31-60.
Results: We identified 79 infants with IEM who were born and remained a member of NCKP at age 3 years. Compared to 1580 matched controls, there was no difference in the proportion of children with IEM up to date for vaccines at 2 years, nor was there any delayed receipt of recommended vaccines during the first year. We also preliminarily identified 322 children with IEM who received any vaccine. Preliminary analysis in this group did not detect an increase in emergency room visits [rate ratio (RR) 0.83, 95% confidence interval (CI) 0.60, 1.14] or hospitalizations (RR 1.1, 95% CI 0.9, 1.4) during the 30 days after vaccination compared to post-vaccine days 31-60.
Conclusion: Children with metabolic diseases in this cohort were vaccinated at rates comparable to healthy children. Although sample size is a limitation, preliminary evidence does not suggest an association between vaccination and an increased risk for serious adverse events.

Emphasis added.

A news story on the subject quoted the session chair where the study was presented:

“These findings are very reassuring,” said Larry Pickering, MD, National Immunization Program, Centers for Disease Control and Prevention, and Emory University, Atlanta, Georgia, who moderated the session at which the study was presented.

“Most of us who take care of kids with inborn errors of metabolism think vaccination is one of the best interventions we can offer them,” he said. “They are at increased risk for devastating complications, even death, from the diseases that the vaccines prevent.”

This is reassuring. Preliminary, yes. I can already see the criticisms, both legitimate and otherwise, that will be levied against this study. but potentially very reassuring. Vaccines are one of the front line interventions in protecting people with mitochondrial disorders.

Let’s see if I can predict the criticisms:

1) not peer reviewed
2) many authors received grant money from vaccine manufacturers.
3) the sample size is small (79 infants)
4) the number of infants with mitochondrial disorders is even smaller (7)
5) it would be good to see a comparison of hospitalizations in the months previous to immunizations (if possible)
6) the time spanned by the study covers a large change in the immunization schedule. The sample size of infants immunized in the current schedule is likely to be rather small.

The sample size is small, but it would be interesting to see if the prevalence of metabolic disorders has increased over this time span. But, as autism has shown us, the correlation=causation arguments can be shaky at best.

Blood Mercury Concentrations in CHARGE Study Children with and without Autism

19 Oct

New paper, just out from the U.C. Davis MIND Institute: Blood Mercury Concentrations in CHARGE Study Children with and without Autism.

The Authors are

Irva Hertz-Picciotto, Peter G. Green, Lora Delwiche, Robin Hansen, Cheryl Walker, and Isaac N. Pessah.

Abstract:
Background: Some studies have reported higher blood Hg levels in persons with autism, relative to unaffected controls. Objectives: To compare blood total Hg concentrations in children with autism or autism spectrum disorder (AU/ASD) and typically developing (TD) controls in population-based samples; to determine the role of fish consumption in differences observed.

Methods: The Childhood Autism Risk from Genetics and the Environment (CHARGE) Study enrolled children aged 2-5 years. After diagnostic evaluation, we analyzed three groups: AU/ASD; non-AU/ASD with developmental delay, DD; and population-based TD controls. Mothers were interviewed about household, medical and dietary exposures. Blood Hg was measured by ICP-MS. Multiple linear regression analysis was conducted (n=452) to predict blood Hg from case status controlling for Hg sources.

Results: Fish consumption strongly predicted total Hg concentration. AU/ASD children ate less fish. After adjustment for fish and other Hg sources, blood Hg levels in AU/ASD children were similar to those of TD children (p=0.75); this was also true among non-fish eaters (p=0.73). The direct effect of AU/ASD diagnosis on blood Hg not through the indirect pathway of altered fish consumption was a 12% reduction. DD children had lower blood Hg concentrations in all analyses. Dental amalgams in children with gum-chewing or teeth-grinding habits predicted higher levels.

Conclusions: After accounting for dietary and other differences in Hg exposures, total Hg in blood was neither elevated nor reduced in CHARGE Study preschoolers with AU/ASD as compared with unaffected controls, and resembled those of nationally representative samples.

I don’t have the time to read and summarize the paper yet. But it looks like another nail in the (already nailed down) coffin lid of the mercury hypothesis.

Sharyl Attkisson interviews David Kirby…and oh is it bad

8 Oct

Have a look for yourself:

http://cnettv.cnet.com/av/video/cbsnews/atlantis2/player-dest.swf
Watch CBS News Videos Online

David Kirby, interviewed by Sharyl Attkisson. Talk about faux-news. For those luckily unfamiliar with Ms. Attkisson, here are some of the pieces done on this blog about her. Ms. Attkisson has a history of interviewing other members of the press and not being critical at all of their unsupported claims. She did this with Bernadine Healy, who made some unfounded claims about the IOM. When a study came out disproving a study by Maddy Hornig on mice and thimerosal that is, Ms. Attkisson blogged the Thoughtful House (Andrew Wakefield) press release on the subject. There’s more, but that gives you a taste of her history.

Today she interviewed David Kirby, author of “Evidence of Harm” and Huffington Post blogger.

To start, David Kirby apparantly has rewritten his book (yes, that is sarcasm). It is titled, “Evidence of Harm, Mercury in Vaccines and the Autism Epidemic: A Medical Controversy”.

But according to the interview, his book isn’t primarily about mercury in vaccines. Instead it is all about “increasing environmental exposures, toxins in children throughout the 1990’s and into the early 2000’s from both mercury background mercury environmental mercury which is on the increase and also mercury and other heavy metals and toxic metals that are included in vaccines that we give our children.”

Notice how thimersosal (mercury in vaccines) is downplayed compared to environmental mercury. That’s called revisionist history. Take a look at the back cover from the book (click to enlarge):

Back Cover from David Kirby's Evidence of Harm

Back Cover from David Kirby's Evidence of Harm

A commenter on this blog called the recent National Children’s Health Survey to be the worst sort of prevalence study. It can get much worse. For example–according to David Kirby, when he went through the subway he didn’t see anyone obviously autistic. Yes, David Kirby, epidemiologist and diagnostician has found a dramatically low prevalence amongst the New York subway riders.

David Kirby reminds us all that Asperger’s syndrome is a disability. Mr. Kirby, go back and tell that to Lenny Schafer, the “commenter of the week” on your blog, the Age of Autism.

If someone made a comment on this blog like Mr. Shafer did he would be booed off the stage. Here’s an excerpt:

And let us hope that the upcoming DSM-V gets clearer about defining autism only as a disability — and kicks the high functioning ND autism squatters onto the personality disorder spectrum where they belong.

Your blog gave him a free T-shirt. Don’t lecture us about disability.

Dr. Thomas Insel, director of the National Institutes of Mental Health and chair of the Interagency Autism Coordinating Committee declined to be interviewed by Ms. Attkisson.

A sincere “good job” goes out to Dr. Insel. After the way Ms. Attkisson showed a clear bias in doing her story on Dr. Offit, I can completely understand Dr. Insel declining the interview.

The second half of the interview discusses Mr. Kirby’s new book, the use of antibiotics on large farms.

No, seriously, they moved from Autism to animal farms.

Way to plug David Kirby’s new book, Sharyl!

Autism rate of 1 percent, and the embargo that wasn’t

7 Oct

Someone at the CDC screwed up. There, I said it.

That’s the bottom line of the story, in case you don’t want to plow through this rather messy story.

Two stories out today are discussing how the 1% autism prevalence story has been handled by the government, the AAP and the media. An emphasis is being placed on how the information embargo was handled and, possibly, mishandled.

One at the Covering Health blog is titled, Autism news raises question: When is an embargo not an embargo?. The second story, at National Public Radio, is titled When News Breaks On Autism, Who Gets It Out First?

Let’s go through the history of this story to unravel a bit of what happened.

This past summer, two studies were in press discussing the autism prevalence in the United States. The first study, based on data from the National Children’s Health Survey, was to be published in the Journal Pediatrics. (This is the one just published) The second study is a CDC report, in the Morbidity and Mortality Weekly Report (MMWR) series. Previous MMWR’s have given us prevalence numbers of 1 in 166 (based on data taken in 2000) and 1 in 150 (based on data taken in 2002).

Someone at the CDC leaked information about these studies to Lee Grossman. Whether Mr. Grossman approached the CDC employee or the other way around is unknown. There also isn’t any information on whether Mr. Grossman was supposed to keep this information confidential.

What is known is that Mr. Grossman publicly discussed this information at an Autism Society of America meeting in July.

Mr. Grossman also discussed this information with Mr. Kirby. How exactly that exchange came about we don’t know. Mr. Kirby has given a version of the story on his blog, but he has also shown himself willing to lie in order to protect a source.

Mr. Kirby blogged information about the two studies on August 11th. He did not name pediatrics as the journal, but he did note that the study would involve the NCHS data.

The pediatrics study was scheduled to come out this week (Monday, October 5). As is usual, the American Academy of Pediatrics released information to the press the week prior. These releases are made so that the press can prepare well researched stories to be published coincident with the paper. The press are not allowed to disscuss the story until the “embargo” was lifted at 12:01 eastern time, Monday Oct. 5.

The embargo system is actually a quite good one. This insures that the press has the time to put together well researched, thoughtful stories on a given topic. The writer who spends a lot of time on a story isn’t penalized by some guy slapping together a quick story to make a scoop. It’s a win-win: the press get to write better stories, and groups like the AAP get good press coverage.

But what do you do when someone has already leaked part of the story? To make it even more complicated, there were really two stories here: the Pediatrics paper published on Monday and the MMWR that isn’t published yet.

Understanding the high level of interest in the story, the U.S. Government decided to hold a conference call with the press. They planned their own data–the MMWR. In this way, journalists covering the Pediatrics story could include the MMWR without having to rely on the bits and pieces leaked by Mr. Kirby.

This call was scheduled for last Friday (Oct. 2) at 3pm.

The information from this call was embargoed. From the NPR story:

“Both the CDC overview and the HRSA study [in Pediatrics] were embargoed, because the subject nature was obviously so similar,” a spokesman for the National Institute of Mental Health told Covering Health. “It just wouldn’t be appropriate to not have the CDC following the same set of guidelines as the HRSA study as it relates to the embargo.”

This call was at 3pm.

The U.S. Government decided early Friday morning to hold a second conference call for autism advocacy organizations. This call was scheduled for 2pm, and did not include embargoed information. They didn’t discuss the details of the papers, just the new prevalence numbers (about 1%).

The Age of Autism blog posted the announcement and call in number.

According to Andrew Van Dam at Covering Health:

CDC spokeswoman Artealia Gilliard told AHCJ on Tuesday afternoon that everything in the 3 p.m. press call was under embargo, while nothing that would have been covered by that embargo was mentioned in the earlier call with the autism community. In particular, Gilliard said, no specific prevalence rate numbers were given out on the call.

“We basically said ‘On Monday, two studies will come out. They will update the prevalence estimate we previously had.’ … It didn’t actually have any of the information that was embargoed.”

Gilliard, who was on both calls, specified further: “I know they didn’t put out numbers in the advocacy call. I know we didn’t say 1 in 100. What we’ve been saying is ‘approximately 1 percent of children.’”

So, we have two conference calls, discussing much the same information (about 1% prevalence). One was embargoed and the other was not.

David Kirby blogged the story right away on Friday. Mr. Kirby starts his post with:

Washington loves to dump its bad news on a Friday afternoon, and on October 2 it confirmed that 1 percent of American children (and by extension, perhaps 1-in-58 boys) has an autism spectrum disorder.

It is possible that Mr. Kirby didn’t know that the Pediatrics study was to be published on Monday. It is possible that he didn’t know about the second, embargoed conference call.

Possible, but very unlikely.

If he knew (and I believe he did), his introduction is highly irresponsible. It fans the flames of the idea that the government tries to bury autism information. No surprises there, as Mr. Kirby has made a career out of fanning those flames.

Mr. Kirby further fans the flames by indicating that the 2pm call was short:

There was no alarm, and little time for questions from the community that was invited to “visit.” After about 15 minutes, questioning was cut off, and the call abruptly ended. I tried three times to ask a question (via a telephone switching system) and so did many other people on the call, which lasted a total of 39 minutes.

As we now know, the government had to prepare for the 3pm call. Perhaps Mr. Kirby didn’t know about that call. Again, that seems highly unlikely.

Mr. Kirby complains of not being able to pose his question. You can go read it if you want, I am not copying it here. The question, in classic Kirby style, is really a lecture putting out the current talking points of the vaccines-cause-autism groups.

Dan Olmsted at the Age of Autism blog mentioned the conference call as well, but his post was brief and not filled with the leading comments Mr. Kirby chose.

Lisa Jo Rudy at autism.about.com read the Kirby and Olmsted pieces (she mentioned this in her piece) and decided to blog the story herself. Unfortunately, she was a bit confused by what was embargoed and what was not–she discussed the Pediatrics paper (which was embargoed). This was reported to the AAP, who contacted Ms. Rudy and Mr. Rudy pulled the piece. The AAP decided that the embargo breach wasn’t so big as to pull the embargo entirely. In other words, they went ahead and kept the rest of the press to the Monday morning embargo date.

On Sunday, 7 hours before the embargo was lifted, Mr. Kirby ran a copy of his Age of Autism blog piece on the Huffington post.

The Age of Autism blog is still trying to fan the flames, pushing the idea that the mainstream media doesn’t want to cover this story. Mark Blaxill posted a piece today, Autism News: Pathetic Non Coverage, discussing how his home-town newspaper (The Boston Globe) didn’t cover the story when the embargo lifted on Monday. He states that “In the meantime, on Tuesday the Globe posted a link to an abbreviated form of the Associated Press story. A day late and a dollar short.”

I don’t profess to know what methods Mr. Blaxill used when he couldn’t unearth the story on the globe.com webiste. I know that I used “autism” as the search term and quickly found this story, which came out Monday, October 5. There is also the abbreviated AP story that the Globe put out on Tuesday, which Mr. Blaxill references.

What can we say about the whole debacle? It is a big mess. It is a big mess that started when someone at the CDC told Lee Grossman of the Autsim Society of America some confidential information. That person at the CDC screwed up.

Isn’t that just a bit sad? Trusting a prominent representative of a major autism organization has been shown, in this case, to be a mistake.

I won’t say that Mr. Grossman made a mistake by talking to David Kirby. An error in judgment, yes. Mistake, no. Mr. Kirby’s track record of presenting any data in a very biased mode to promote vaccines-causing-autism is quite well established.

I didn’t see any mainstream press coverage that included any of Mr. Kirby’s talking points. He was able to get a prominent spot in the google news searches on autism with his Huffington Post piece.

The main fallout seems to be (a) the CDC will probably clamp down on giving out information and (b) the press has an impression that autism advocates are irresponsible with information.

Do we need an epidemic for people to take autism seriously?

6 Oct

There is a lot of press coverage around the recent Pediatrics study and the government’s stand that the prevalence of autism spectrum disorders (ASD’s) is about 1%. As I read the articles and, especially, some of the blogs, I am left with the question: why do some people feel that we need an epidemic in order for autism to be taken seriously?

Dr. Geraldine Dawson, chief science officer for Autism Speaks responded to the announcement with:

“There is converging evidence that autism spectrum disorders affect about one percent of the population. This study further emphasized that autism affects boys at a significantly higher rate. It is imperative that more resources be given to autism research so we can understand the causes and biology of autism and develop more effective treatments.”

Autism Speaks is a group that depends on donations, and they aren’t making unfounded calls of an epidemic.

An ASD rate of 1% or more has been shown in studies for at least 10 years. The just released study used the National Child Health Survey 2007 data. This raised a bit of a stir when the study results were leaked recently, and I spent a lot of time looking at the raw data. I also pointed out that Joseph at the Natural Variation-Autism blog discussed a number of studies pointing to a 1% or higher prevalence in his post Moving Toward a New Consensus Prevalence of 1% or Higher.

These studies weren’t hidden or obscure, either. Even Dr. Andrew Wakefield, the man most responsible for the notion that the MMR vaccine causes autism, cited the Swedish study in his early patent application.

The studies are known to researchers in the field. In a Time magazine story out Monday, Prof. Richard Roy Grinker is quoted:

What’s significant is that the study lines up well with other, more rigorous studies finding a 1% rate of autism. “It provides what scientists call convergent validity: no matter how you shake the bushes, you come up with this 1%,” says Richard Roy Grinker, an autism researcher at George Washington University who has worked to determine ASD prevalence in South Korea.

As noted, Prof. Grinker’s team has studied the ASD prevalence in South Korea. At the Autism Speaks “Decade for Autism” kickoff at the U.N., one of Prof. Grinker’s collaborators, Dr. Young Shin Kim, noted that the prevalence in Korea is likely in line with other countries–1 in 100 to 1 in 200.

If you think the recent jump from 1 in 150 to 1 in 91 was a shocker for the United States, wait until the Korean prevalence jumps from 1 in 10,000 to, say, 1 in 150. Will they claim epidemic, or will they realize that the previous prevalence method seriously under counted the autistic population?

Prof. Craig Newschaeffer of Drexil University is quoted as in Time Magazine saying:

“Nonetheless, the survey reinforces what we have come to understand over the past decade — that autism is much more common than previously thought.”

It is safe to say that Geraldine Dawson, Richard Roy Grinker and Craig Newschaeffer take autism very seriously. And yet they (and the vast majority of the autism research community) do not believe in or feel the need to promote autism as an “epidemic”.

The major autism research organizations aren’t claiming an epidemic. Autism Speaks, Simons Foundation, and the Nancy Lurie Marks (NLM) Family Foundation aren’t calling this an epidemic. Even the Autism Society of America didn’t call the news an “epidemic” in their press release. My guess is that no one will be shocked that the Autistic Self Advocacy Network didn’t call the latest prevalence figures a sign of an epidemic.

Look outside the autism communities. Do we need to hear “epidemic” in order to take disabilities seriously? No.

One can take autism very seriously and still not consider it an epidemic. I realize that many readers of this blog won’t consider this news at all.

I know many people can’t see how jump in the number of ASD diagnoses (or, in the case of this study, parent-reported autism diagnoses) doesn’t mean an epidemic. But many of us have been pointing out how the previous ASD prevalence values were under counts.

Frankly, I find it very disturbing that we likely haven’t been identifying all the autistic kids and adults for all these years.

I find it more disturbing that many of the so-called autism advocacy organizations have been so willing to ignore the possibility that the prevalence estimates were an under count–all in the name of promoting vaccine causation.

The most cited autism prevalence number up until now was 1 in 150. This came from a CDC report called an MMWR, published in 2007, Prevalence of Autism Spectrum Disorders — Autism and Developmental Disabilities Monitoring Network, 14 Sites, United States, 2002.

The study looked at 8 year olds in 2002–children born in 1994. The prevalence was 1 in 150. Another way to put that is 67 per 10,000.

These same children were 13 in 2007, when the NCHS survey data was taken. This is the data used for the 1 in 91 prevalence estimate released this week.

Take a look at Table 1 from the recent Pediatrics study. The prevalence for 12-14 year olds is 118 per 10,000.

So, one study, using one methodology, using data from 2002 and published in 2007 gets 66 per 10,000.

Another study, using different methodology, using data from 2007 and published in 2009 get 118 per 10,000.

This for the same group of kids.

Is there an epidemic? Is there an epidemic that nearly doubles the autism prevalence kids between the time they are 8 and the time they are 13?

Autism advocacy doesn’t need an epidemic to be taken seriously. In fact, pushing an epidemic will make sure we aren’t taken seriously.

Autism rate 1 in 100 in American Children?

5 Oct

A new study in the Journal Pediatrics claims a prevalence of Autism Spectrum Disorders of 110 per 10,000 (1.1%). This is notably higher than previous estimates based on the CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network.

There is little doubt in my mind that this will get a lot of media attention.

The paper is:

Prevalence of Parent-Reported Diagnosis of Autism Spectrum Disorder Among Children in the US, 2007

by

Michael D. Kogan, PhD,Stephen J. Blumberg, PhD, Laura A. Schieve, PhD, Coleen A. Boyle, PhD, James M. Perrin, MD, Reem M. Ghandour, DrPH, Gopal K. Singh, PhD, Bonnie B. Strickland, PhD, Edwin Trevathan, MD, MPH, and Peter C. van Dyck, MD, MPH

Here is the abstract:

OBJECTIVES: The reported increasing prevalence of autism spectrum disorder (ASD) and attendant health and family impact make monitoring of ASD prevalence a public health priority.

METHODS: The prevalence of parent-reported diagnosis of ASD among US children aged 3 to 17 years was estimated from the 2007 National Survey of Children’s Health (sample size: 78 037). A child was considered to have ASD if a parent/guardian reported that a doctor or other health care provider had ever said that the child had ASD and that the child currently had the condition. The point-prevalence for ASD was calculated for those children meeting both criteria. We examined sociodemographic factors associated with current ASD and with a past (but not current) ASD diagnosis. The health care experiences for children in both ASD groups were explored.

RESULTS: The weighted current ASD point-prevalence was 110 per 10,000. We estimate that 673,000 US children have ASD. Odds of having ASD were 4 times as large for boys than girls. Non-Hispanic (NH) black and multiracial children had lower odds of ASD than NH white children. Nearly 40% of those ever diagnosed with ASD did not currently have the condition; NH black children were more likely than NH white children to not have current ASD. Children in both ASD groups were less likely than children without ASD to receive care within a medical home.

CONCLUSIONS: The observed point-prevalence is higher than previous US estimates. More inclusive survey questions, increased population awareness, and improved screening and identification by providers may partly explain this finding.

The authors used the National Survey of Children’s Health. We have discussed the NSCH data previously on this blog.

The data are based on a phone survey, and use parent reports, not direct observations. For example, the researchers didn’t actually test any children, but they instead relied upon the phone survey answers to questions like:

For each condition, please tell me if a doctor or other health care provider ever told you that [your child] had the condition, even if he/she does not have thecondition now….Autism, Asperger disorder, pervasive developmental disorder, or other ASD?

The 1412 who answered yes to that question were asked:

Does [your child] currently have autism or ASD?

With 913 answering yes.

78,037 families were polled. This was a response rate of about 51% (assuming that all calls that were unanswered were residences and not busisnesses).

I have discussed raw data from the 2007 NCHS. By contrast, the researchers corrected the raw data for various factors that could cause systematic errors.

Estimates were weighted by using survey sampling weights available from the National Center for Health Statistics. These weights reflect the inverse of the probability of being selected for the survey and were adjusted to account for nonresponse and noncoverage of households without landline telephones. Weighted estimates are representative of the US noninstitutionalized population of children aged 3 to 17 years.

After correcting for these factors, the authors came up with a prevalence value of 110 per 10,000 children. (1.1%)

Parents were asked about the severity of their child’s ASD. Most answered mild. The breakdown is

Mild: 54 per 10,000
Moderate:37 per 10,000
Severe: 18 per 10,000

The age distribution wasn’t flat, but neither did it show the huge variation one would expect from special ed data, CDDS data or other sources often cited.

3-5 years old: 85
6-8 years old: 132
9-11 years old: 138
12-14 years old: 118
15-17 years old: 77

There is a higher prevalence amongst males than females, as expected. The prevalence amongst Hispanics (103/10,000) and non-Hispanic African Americans (61/10,000) are both lower than amongst whites (125/10,000).

Many of the results are shown in Table 1 from the study, shown below.

Table 1 of prevalence report using NSCH data

Table 1 of prevalence report using NSCH data

Aside from the overall prevalence number, the second hot topic from the survey is the large number of children whose parent answered yes to “have you ever been told that your child has an ASD” but who answered no to “does you child now have an ASD”.

People are referring to these children as having “lost” their diagnoses. They account for about 0.4% of the total survey.

The authors spend a significant amount of time discussing the possible reasons why some children may have “lost” a diagnosis. We have already discussed some of the reasons on this blog.

The bottom line is, there isn’t enough information in the survey to tell. We do know that most of the children who “lost” an autism diagnosis had some other disability.

It needs to be stressed–there is no confirmation that these children ever had an official diagnosis of autism. That isn’t just for the group that “lost” autism, but for the entire group.

This is a significant limitation of this study. I have stated before, I think this sort of survey is good for generating questions for future studies. For that purpose, these surveys are valuable. They are faster and cheaper than a full study. But it is far from the sort of data that should be used to claim a definitive prevalence.

I expect to see a lot of press coverage of the new “prevalence”. While this study is a good, and it is consistent with many studies that show a prevalence in the 1-1.5% range, the data just aren’t strong enough to make such definitive statements.

Edited to add:

The USA Today story on this study has a quote that I think sums it up quite well:

Pediatrician Susan Levy, founder and director of the Regional Autism Center at Children’s Hospital of Philadelphia, notes that Kogan’s study is based only on what parents said about their children, not information from doctors involved in their care.

“For what it is, it’s very well done, and I don’t mean that critically,” she said in an interview. “It is one method of getting a handle of how many people in the country have this disorder. Is it the best method? No, but it is one way of approaching it.”

Do techie parents have more autistic kids?

2 Oct

This is the stuff of legend. So says the Simons Foundation blog in discussing a new epidemiological study out of California. A previous study reported that fathers of ASD kids are more likely to be engineers. The idea got into the mainstream media (and deep into the public psyche) when Wired Magazine even called the phenomenon the “Geek Syndrome“.

Well, someone checked. Someone being Gayle Windham, Karen Fessel and Judith Grether. If you are an autism epidemiology geek, you will recognize at least some of those names.

Here’s the abstract:

Autism spectrum disorders in relation to parental occupation in technical fields
Gayle C. Windham, Karen Fessel, Judith K. Grether

A previous study reported that fathers of children with autism spectrum disorders (ASD) were more likely to work as engineers, requiring systemizing skills, and suggesting a distinct phenotype, but alternatively this may have been related to selection biases. We conducted a population-based study to explore whether fathers, or mothers, of children with ASD are over-represented in fields requiring highly technical skills. Subjects included 284 children with ASD and 659 gender-matched controls, born in 1994 in the San Francisco Bay Area. Parental occupation and industry were abstracted verbatim from birth certificates. Engineering, computer programming, and science were examined as highly technical occupations. To limit bias by parental socio-economic status, we selected a referent group of occupations that seemed professionally similar but of a less technical nature. Odds ratios (ORs) and 95% confidence intervals (CI) were calculated by logistic regression, adjusting for parental age, education, and child race. Mothers of cases were somewhat more likely to work in hi-tech occupations (6.7%) than mothers of controls (4.0%, P=0.07), but little difference was observed among fathers, nor for engineering separately. Compared to parents in other white collar occupations, the adjusted OR for highly technical occupations among mothers was 2.5 (95% CI: 1.2-5.3) and among fathers was 1.3 (95% CI: 0.79-2.1), with no evidence of a joint effect observed. Our results regarding maternal occupation in technical fields being associated with ASD in offspring suggest further study to distinguish parental occupation as a phenotypic marker of genetic loading vs. other social or exposure factors

To summarize it even more: mothers in “highly technical” jobs had a 2.5 times higher chance of having an autistic kid. There isn’t a clear statement for fathers. Also, there isn’t evidence of a “joint effect”. I take that to mean that the “geeks marrying geeks have more autistic kids” idea didn’t pan out.

They can’t say why mothers in highly technical jobs have more autistic kids. This makes it a study that can be quoted by everyone. “It’s genetic, see mothers in technical jobs have more autistic kids”. “It’s social, mothers in technical jobs are more likely to know about autism and get their kids diagnosed”. “It’s environmental, mothers in technical jobs are exposed to more toxins”.

In the end, this is no joke. We need to understand all the factors that can affect epidemiological studies. Epidemiological data for autism are pretty muddy, in my opinion. A lot of things have happened in the last 20 years (or more) that have changed the “rate” of autism diagnoses. Anyone who wants to find one of the many causes of autism (which is, as we all know a plural: autisms), needs to understand these factors.

← Older Entries
Newer Entries →