Saturday, December 30, 2006

US$780,000

That's about how much Andrew Wakefield received from anti-vaccination lawyers, according to an article by Brian Deer titled MMR doctor given legal aid thousands. Some of the stuff that goes on in autism "research" is really sickening, isn't it?

Kudos to Brian on some great investigative reporting.

Wednesday, December 27, 2006

What Do Parents Attribute Regression To?

Wakefield et al. (1998), despite having been partially retracted, is the paper considered mostly responsible for an autism-related anti-vaccination scare that started with the MMR vaccine and subsequently evolved to include thimerosal-containing vaccines (TCVs). The MMR vaccine has been the focus of hype mostly in the UK, whereas TCVs are most often blamed for autism in the US.

If you search the VAERS database for reports filed in all of 1997 on MMR-attributed autism, you will find 16 reports of adverse events. If you do the same search in all of 2002, you will find 120 reports. That gives you an idea of the effect of MMR hype on what parents attribute autism to. Thankfully, the number of such reports appears to be declining in recent years, with only 40 in all of 2005.

Lingam et al. (2003) found that not only did the rate of attribution of regression to the MMR vaccine changed post-Wakefield, but some parents apparently changed their story as well.
Widespread public concern about the possible relation between autism and MMR began in August 1997, with the pre-publication release of information about the Wakefield study, which attracted considerable and ongoing media attention. The date at which onset of developmental regression was first recorded in the notes was obtained for the 106 cases. After excluding unvaccinated cases and those vaccinated when aged over 24 months (of whom all but one were children vaccinated in the 1988-89 catch-up campaign), we found MMR was reported as the trigger in 6/30 (20.0%) post-August 1997 compared to 2/46 (4.3%) before August 1997 (p = 0.052).

From August 1997 the reported presence or timing of regression changed in 13 cases. For six of these, regression was mentioned for the first time after August 1997, even though many health professionals had seen these children before this date. In seven cases the recorded timing of onset of regression changed in relation to MMR: six closer, one further away.

But there is some other data of interest in Lingam et al. (2003) which I wanted to go into. They survey parents about triggers thought to cause regression.
In 44 (42%) of the 106 children with detailed information on regression, a specific trigger was mentioned as a possible cause. The most common (13 children) was a household or social change such as the birth of a sibling, then vaccination (12 cases). Other triggers mentioned were: viral and bacterial infections (n = 7), seizures (n = 7), postsurgery (n = 2), and other causes (n = 3). The MMR vaccine was mentioned specifically in eight of the 12 cases where a vaccine was suspected. Although families would not have been directly asked about this possibility, this finding suggests that very few parents (less than 2% in this cohort) considered that MMR vaccine might have triggered their child's autism.

Interestingly, in this post-Wakefield survey, there is one trigger parents seem to attribute regression to more often than vaccination: Household stress, such as the birth of a sibling.

In case there are doubts about this, let's look at another survey on language regression, Shinnar et al. (2001) (full HTML text can be temporarily found here). The following is what they found.
Fifty-two families (29%) reported a trigger to the regression (Table 2). The most common triggers reported included family stresses (n=23), such as the birth of a sibling (n=10) or moving (n=7), seizures (n=13), or infectious/immunologic triggers (n=14).

More specifically, they found that only 8% of parents attributed regression to immunization, compared to 19% who blamed the birth of a sibling, and 44% who blamed family issues in general.

It is often said that autism researchers would do well to pay attention to parental experiences. There is some definite merit to this idea, of course, as there is merit to the notion that researchers should listen to autistics themselves. It follows that there must be a whole subfield of autism science dedicated to studying the link between family stress and autism/regression, right? Well, I'm unable to find much of anything about this link through Google Scholar. But surely, the potential link must have been mentioned as part of the Combating Autism Act, correct? No, apparently not. At least there must be mailing lists established to discuss this link or blogs where it has been mentioned, right? Not that I know of. I actually believe this is the first blog post where the link between stress and regression is the main topic of the post.

Why might this be? I suggest it's because there won't be class-action lawsuits that address the stress caused by the birth of siblings. There aren't specific big corporations that can be blamed for family issues. There is no role for the illuminati to play. And perhaps most importantly, it seems difficult to come up with grandiose promises of cure for stress-induced autistic regression.

Further reading

-Whatever Happened To? (Joel)
-Is the TV Hypothesis more Plausible than the Thimerosal Hypothesis? (Joseph)

Friday, December 22, 2006

On The Validity Of Self-Diagnoses

Via Brett I've learned of an article titled Study: Most Self-Diagnosed "Asperger's" Patients Just Assholes claiming to report on a study published in The Lancet, no less. After checking out the website where the article is posted, www.ridiculopathy.com, it's clear this is just one of their spoofs. Nevertheless, I think there's a reason why someone came up with the idea of making fun of self-identified adult autistics, and this is something that should be addressed and debated by our community.

It surely has to do with the fact that 30 years ago there was no one identified as having Asperger's, yet there is probably nothing biologically new about today's adults. I think most people would prefer to keep the ad-hoc labels of the past ("asshole" being one of them) as opposed to having to deal with (and perhaps even accept) the impairments and peculiarities of others. A similar theme was explored by the TV show House, where the main character was suspected of having Asperger's but was later characterized as having to face the fact that he was merely being a "jerk".

Much of the importance of the issue rests in the fact that opponents of autism self-advocacy attempt to use the existence of self identification to their advantage. Think Lenny Schafer. Never mind that undiagnosing someone over the internet is obviously less valid than any non-professional self-assessment.

The "explosion" in adult diagnoses and self-diagnoses of ASD certainly seems to parallel that of diagnoses in children. That is, they started to occur mostly in the 1990s, and really exploded in the late 90s. I first learned about Asperger's in 1998, which is roughly when the internet was experiencing a substantial boom. Doubts about the validity of ASD diagnostic labels are not restricted to adulthood, mind you, as evidenced by an article by one Katie Grant titled Some 'autistic' children aren't ill, they're just badly behaved (which was not a spoof, sadly).

Before I continue, I think a personal disclaimer is in order. I do have what I consider to be a diagnosis, given to me by my son's psychiatrist. It was a quick diagnosis and it's not in writing, mind you, but I don't really have use for anything beyond that. Plus I have an autistic son, a dad with clear autistic characteristics in early childhood, and my own childhood history which includes hyperlexia. There are many other relevant facts about my family and myself which I won't go into. So I have no doubt I'm autistic, and neither does my wife. My parents seem to be mostly accepting of the fact that I'm autistic at this point.

But in many cases a diagnosis of ASD, particularly a self-diagnosis, might leave room for doubt. The matter is complicated by the fact that there are no medical tests for ASD and it's unlikely there will ever be a simple, accurate test.

Whether self-diagnoses are valid or not is primarily a scientific question in my opinion. Intuitively, it seems to me people would be able to determine what they are most of the time. But while it would not make sense for people to be wrecklessly giving themselves false psychiatric labels (consider the potential impact on any employment, for example) error is always a possibility, as is hypochondria.

I'm aware that professionals warn against self-diagnoses of ASD. But is there a study which documents the inaccuracy of self-diagnoses of ASD specifically? Not that I know of. I think such warnings are based on educated hunches, nothing more.

While studies on the validity of self-diagnoses of ASD don't appear to exist, I wouldn't say nothing is known about them. Let's look at what I believe are the two most often used instruments involved in self-diagnosis.



The owner of the Aspie Quiz makes some relevant claims about that instrument. For example, that the test has been adjusted over time based on the performance of each question. And that self-diagnosed autistics, surprisingly, tend to score slightly higher than diagnosed autistics. Interesting as these claims are, it's important to note there are no published studies on the validity of the Aspie Quiz.

The AQ Test, on the other hand, has been studied on multiple occasions. For example, Woodbury-Smith et al. (2005) found the test to have good discriminative validity at a threshold of 26. What this means is that if you score 26 or lower in the AQ Test, it is very unlikely that you are autistic. This only tells us about the screening properties of the tool, not about its potential use as a diagnostic instrument. But let's look at Baron-Cohen et al. (2001) where 11 students scoring 32 or higher were interviewed. All of the 11 met 3 or more DSM-IV criteria and 7 of the 11 met "threshold" on these criteria. (I believe "threshold" means clinical significance). So it appears that the AQ Test has about 64% accuracy at a cut-off of 32.

I would conclude that if you score higher than about 33 in the AQ Test, you have the 3 major features of autism (impaired socialization, communication difficulties and obsessive interests/repetitive activities), and these cause problems in the areas of employment, education or social/family life, then there is little doubt you are autistic. This is just my opinion, which is that of a non-psychiatrist. Do I expect most psychiatrists to disagree with this conclusion? Of course.

Thursday, December 21, 2006

David Kirby Plays Fast and Loose With Facts

I've discussed fabrications related to autism before. A much more annoying phenomenon occurs when a single individual goes around making up significant claims that simply cannot be substantiated. I'm talking about David Kirby.

An article published by Herald Community Newspapers Online has irresponsibly echoed such claims by Kirby. The most outrageous claim in the article is perhaps the following:

He pointed to Denmark and Sweden to support his theory that there was a connection between an autism increase and Thimerosal. In 1992, both countries removed the mercury preservative from their vaccinations and have seen a remarkable drop in autism.


Not only is there no data to substantiate this claim, but it is known that what actually happened is the opposite of what this claim states. (At least in Sweden that is obvious, and although disputed to an extent in Denmark, there's no reason to think their administrative autism rates have declined at any point in time). I don't know if the paper quoted Kirby correctly, but there are several other direct quotes attributed to David Kirby. For example:

There was a huge spike in autism in 1992 when the Hepatitis B vaccine was added to the regular vaccination schedule for babies.


If you look at a graph of administrative prevalence of autism in the U.S. you will see there is an increase in the prevalence between 1992 and 1993, but it is a very small increase. There is no "huge spike" around 1992. There are no "huge spikes" at any time, but a gradual increase throughout the 1990s and beyond. The growth in prevalence between 2002 and 2003, for example, is much larger than anything that occurred around 1992.

Kirby on historic prevalence:

There were 1 in 10,000 children with autism in 1987 in the United States before the addition of Thimerosal.


This is absolutely not true, and cannot be substantiated by any epidemiological study. It is not clear where this statistic comes from at all, and I do not believe Kirby can produce an original source, nor can JB Handley, who has been asked to source the same claim previously. The first significant epidemiological study of autism was Lotter et al. (1967) which found a prevalence of 4.5 in 10,000 for Kanner autism as operationalized by Lotter. For a prevalence study around the year Kirby cites, see Ritvo et al. (1989), which found a prevalence of 4 in 10,000 in Utah.

There is a comment by one Michelle Soodek in the article which I wanted to note as well:

She reasoned that if there were just as many people with autism when she was a child, than where are the institutions and facilities to house all of these people that would now be adults?


Ms. Soodek is repeating a common mistake in reasoning by those who embrace the autism epidemic concept. She is assuming that most children currently diagnosed with autism would be institutionalized, and that rates of institutionalization for children diagnosed today is the same as that of children diagnosed 20 years ago. As I have shown using CDDS data, the total number of institutionalized developmentally disabled individuals in California has declined a little in the last 14 years. More institutions will not likely be needed in the future. To suggest otherwise is nothing but fear mongering. She is also promoting the idea that autistics naturally belong in institutions, which is a deplorable thing to do even if it was unintentional.

That's enough about that article. Let me now look at some of David Kirby's history of dubious claims. They started early on. For example, an infamous claim from his book, Evidence of Harm, was that Asperger's Syndrome is "also known as idiot-savant syndrome". This is clearly false if you consider the history of the terms.

What about his promotion of Evidence of Harm as the work of an impartial journalist? These days he refers to thimerosal hypothesis skeptics as "mercury defenders".

A more significant example of dishonesty is documented by Kevin Leitch. In an interview with the New York Times in 2005, David Kirby stated that autism rates should drop by the end of 2005. He later established his current goalpost of 2007 when he discussed the California numbers with Citizen Cain. Kev requested a clarification from Kirby, which was the following:

The Times misquoted me. I actually asked for a correction, but did not receive one. What I told the reporter is that "we should know in the next few years."


Kev actually apologized to David Kirby before he contacted the New York Times to verify Kirby's account. The Times replied as follows:

Prior to publication, we read the entire passage relating to this matter to Mr. Kirby. He approved it.


I do not know that Kirby addressed the issue further after Kev caught him lying.

I'm sure there are further examples of dishonesty from Mr. Kirby. Readers can provide additional instances if they wish to.

There will be a public debate between David Kirby and Arthur Allen on January 13 at 10 a.m. in the Price Center, University of California, San Diego. This debate is sponsored by TACA and Generation Rescue, who will no doubt attempt to stack up the audience against Mr. Allen. It would be nice if members of the skeptical community can attend.

I am sure Mr. Kirby will try to introduce some of these "facts" of his in the debate. The problem with a spoken debate format is that it allows such fabrications to occur. In that format it is more difficult to call your opponent on dubious claims and successfully show that the claims cannot be sourced. This is likely one reason why you don't see David Kirby debating in blogs, while accepting to debate in a standard spoken format. It has nothing to do with visibility, in my opinion, considering, for example, that Kev's blog has at least twice the readership size of the Autism Speaks website.

Wednesday, December 13, 2006

Kirby, Olmstead Shoot Selves in Foot

David Kirby is well aware that 2007 is right around the corner. You can tell by the rather unusual tone of his latest post. He's no longer even pretending to be objective. How long before he starts calling anyone who disagrees with him a Big Pharma Shill?

So what is Kirby so worked up about? It appears that he has learned from Dan Olmstead of a NIH report titled "Thimerosal Exposure in Pediatric Vaccines" about potentially serious methodological problems in ecological studies that use the VSD database. I don't know if Kirby read the report, but I did. This is actually a very well thought out report which ideally should have been done 6 years ago. But Kirby seems to think this report is evidence of an association between autism and thimerosal, or at the very least evidence that undermines lack of evidence of an association. Something like that.

Verstraeten et al. (2003), the VSD study in question, found statistically significant associations between thimerosal and a couple neurological outcomes in some HMOs, but the associations were not consistently found in other HMOs. Because of these conflicting findings, the study authors called the results "neutral", meaning that the study can't tell us if thimerosal is associated with neurodevelopmental disorders or not. Now the NIH has come up with a list of methodological problems that put in further doubt any VSD findings by Verstraeten et al. in relation to thimerosal. In other words, the neutrality (or non-informativeness) of the findings has been strengthened.

Surprisingly, Kirby's reading of the report conflicts with his other views, because it completely undermines the foundations of the Simpsonwood conspiracy theory. You see, Verstraeten et al. were supposed to have found significant associations between thimerosal and neurodevelopmental outcomes beyond those that were reported in 2003. But now Kirby is endorsing a NIH report which says that ecological studies on the VSD database, specifically those done by Verstraeten et al., are likely flawed. I'm not sure if Kirby realizes this. If he does, he's being duplicitous. If he does not, he just shot himself in the foot.

Furthermore, there is a quote by Thomas Verstraeten which is often used to argue in favor of the thimerosal association:

Personally, I have three hypotheses. My first hypothesis is it is parental bias. The children that are more likely to be vaccinated are more likely to be picked up and diagnosed. Second hypothesis, I don't know. There is a bias that I have not yet recognized, and nobody has yet told me about it. Third hypothesis. It's true, it's thimerosal. Those are my hypotheses.

(Source)

Verstraeten was likely being honest in his assessment. What the NIH report has done, effectively, is provide many possible "Second hypotheses".

Kirby also believes the Verstraeten et al. study is the cornerstone of the case against the thimerosal hypothesis. It's not clear why he believes that is true. I think one of the best studies on the matter is Fombonne's out of Canada. Even if you don't care to analyze those findings, it's enough to consider that thimerosal was fully removed from pediatric vaccines in Canada in 1994, and the prevalence of ASD among Kindergarten children there is currently around 1%. You don't have to be an epidemiologist to realize what the implications of these facts are. Kirby thinks Fombonne's findings are inconclusive, but again, it is not clear what he bases that on. I imagine it's the very weak rebuttal by SafeMinds, an organization that is apparently no longer even putting minimal effort into arguing its case.

Kirby makes light of the Andrews et al. (2004) study out of the UK. That study found statistically significant negative associations ("protective" effects) between thimerosal and autism. Kirby's interpretation of those findings is either naive or desingenuous. If thimerosal is phased out at the same time the incidence of autism increases, it is obvious that the study will find that children not receiving thimerosal tend to become autistic more often than those vaccinated with it. So the finding of a statistically significant negative association is not surprising. It doesn't mean thimerosal protects against autism, but simply that there were coincidentally divergent trends of thimerosal exposure and autism incidence. Incidentally, if a VSD study were done on the birth year cohort expanding, say, 1998 to 2002, it would also find a "protective effect" of thimerosal, no doubt.

Back to the NIH report. I actually welcome this report, and I'm not just saying this now that it has come out. Back on November 20, I analyzed claims about early drafts by Verstraeten et al. In that post I mentioned several ridiculous negative associations found between various outcomes and thimerosal. I argued that the findings of Verstraeten et al. cannot be taken at face value, and that while VSD has its merits, "this doesn't mean VSD is impervious to confounds beyond random error." I further stated that "VSD still records outcomes based on existing diagnoses, not the results of whole population screenings. In a cohort of children expanding many years, recent diagnoses are not necessarily equivalent to older diagnoses. Surely, things like coincidental trends and left censorship could have an impact on any findings." What does the NIH report say?

The panel identified several serious problems that were judged to reduce the usefulness of an ecologic study design using the VSD to address the potential association between thimerosal and the risk of AD/ASD. These included uncertainties in case ascertainment, heterogeneity of business practices within and across managed care organizations (MCOs) and their systematic changes over time, misclassification of exposure status using comparisons of before vs. after removal of thimerosal from most childhood vaccines, and the inability to control for temporal changes in awareness, diagnostic practices and potential confounding factors.


(Emphasis mine)

I'm glad there are people who think about these things in more professional depth, believe in the self-correcting principle of science, and are willing to criticize existing scientific work, no matter who did it.

The NIH panel makes some interesting proposals for future VSD studies and they are apparently taking suggestions from the autism community. I think the biggest potential problem of a VSD study is that of coincidental trends (specifically, thimerosal exposure rising at the same time as administrative incidence of ASD in the early 1990s). That is why I think a VSD study should not look at a cohort expanding many years, but maybe only one year. This is difficult, nonetheless, because the number of children with a given outcome in an HMO is small. An alternative is to look at a cohort where the average thimerosal exposure was roughly constant over time (e.g. 1995 to 1998).

Other confounds are not as easy to control for I'd imagine. Either way, more studies would be good to have. Matters that appear unresolved don't help things move along.

Tuesday, November 28, 2006

Fabrications About Autistics

In this post I would like to provide three clear, documentable examples of outright fabrications about autistics. For whatever reason some people seem to be under the impression that autistics are fair game when it comes to making up facts and statistics.

1. Rate of Institutionalization

In Instant Institutionalization, Michelle Dawson informs us of a claim about institutionalization rates from a "fact sheet" that is disseminated among Canadian politicians:

Without treatment, autism is a lifelong affliction that results in 90% of afflicted individuals placed in institutions and residential facilities, facing an unfulfilling and bleak existence for both the individual and family members.


Michelle Dawson notes that the 90% figure cannot be supported by peer-reviewed science, and challenges autism advocates to provide a supporting citation.

I wanted to go further than that and verify if the figure can be supported by administrative data. Unless culture in California and Canada are considerably dissimilar, we should be able to learn something about institutionalization from the California Department of Developmental Services quarterly client characteristics report.

Before looking at the data, I should emphasize that, as a rule, only individuals with autistic disorder are eligible for CDDS services. The data is not supposed to include those with PDD-NOS or Asperger's Syndrome. Further, I will look at data for adults, who by and large were probably diagnosed under DSM-III or Kanner's criteria, and who could not have been part of an ABA program in early childhood. Adults who at some point were in the CDDS system and decided they no longer required its services for any reason are obviously not included in the data.

From the Q3 2006 report, we learn that 3,089 autistic persons do not live independently or at home with a parent/guardian. The report also says that there are 7,015 autistic adults (18 or older) in the system. So at most 44% of adult autistics in California do not live with family or independently. The actual figure could be lower depending on the number of children who do not live at home.

Of those not living independently or with family, the vast majority live in Community Care. If we only count Institutional Care Facilities as "institutionalization", the figure is at most 4.75%. That's correct, less than 5%. It should also be noted that all of these rates are falling rapidly.

2. Severe Behaviors

There are people who go around implying that autistic children are, in general, little monsters who pose a danger to themselves and others. For example, Mark Geier stated the following in a Radio Liberty interview:

A lot of these kids are so severe, you know, they don't say a word, they attack everybody, they break their mothers arm. These are really, really aggressive kids.


Break their mother's arm? I wonder how often that really happens. The CDDS report won't tell us that, but it does have a category called "Severe Behaviors". From the latest report we learn that 16.31% of autistics in the system are classified as having "severe behaviors". That's roughly 1 out of 6.

3. Mental Retardation

Professor Meredyth Goldberg Edelson has challenged claimed rates of mental retardation in autism which are found in the scientific literature. This was recently reported in the press:

Goldberg Edelson reviewed 215 studies on autism, dating to 1937, which made 223 claims about the rates of mental retardation in autism. Only 58 of those claims were supported by data, she found, and most researchers stated their results without reporting how they measured intelligence.

Most of the studies that measured intelligence used tests that were inappropriate, Goldberg Edelson found.

"Many times, if the researchers had a child they couldn't test, they just assumed he or she was retarded and assigned a low IQ score," Goldberg Edelson said.


In the latest CDDS report we find that 28% of autistics of all ages in the system are classified as having some level of mental retardation. It's not clear how this determination is made. It is probably fair to assume there is some misclassification, and that a different type of testing would yield a different figure. In some cases a child may be presumed to be mentally retarded on the basis that he or she is unable to understand or comply with simple instructions. But the CDDS does have an "Unknown MR" category, which currently holds 6.75% of autistics in the system.

The issue is not that it is bad for mental retardation to be associated with autism. Mental retardation is a neurological difference which does not in any way invalidate disability rights, neurodiversity or self-advocacy. The issue is how easily facts and statistics are fabricated when it comes to autistic people.

Thursday, November 23, 2006

Debunking the Costs of Autism

A press release came out back in April titled Autism Has High Costs to U.S. Society, claiming that "it can cost about $3.2 million to take care of an autistic person over his or her lifetime" and that "caring for all people with autism over their lifetimes costs an estimated $35 billion per year."

This is nothing but bigotry of the highest order. It's no different to this as far as I'm concerned.

I'm aware such costs are studied in the context of a medical model of disability. The underlying assumption of this model is that disability is a burden that should be eliminated/cured. That's about the entire scope of the model. Never mind the track record of the model, or how realistic its goals, considering the inescapable reality that every person in the world will experience disability in their lifetimes, unless they die first.

What I would like to do in this post, nonetheless, is scrutinize the numbers in the report.

Let's start with the $3.2 million figure, assuming a life expectancy of 70 years for an autistic person. This would mean $41,714 is spent annually on the average autistic individual. I don't doubt some parents choose to spend that much in expensive ABA programs and such, but does it seem realistic that this is the average annual expenditure for an autistic from the day they are born until the day they die?

So how does the author arrive at this number? He first looks at estimated direct costs:

Direct costs include direct medical costs, such as physician and outpatient services, prescription medication, and behavioral therapies (estimated to cost, on average, more than $29,000 per person per year) and direct non-medical costs, such as special education, camps, and child care (estimated to annually cost more than $38,000 for those with lower levels of disability and more than $43,000 for those with higher levels).


Medical costs are documented in Croen et al. (2006). The excess annual medical costs for autistic children relative to controls is $1865, due mostly to the prescription of psychotropic medications. But that's for children. What of the lifetime cost? Let's multiply that number by 20, which gives $37,300.

As to therapies, while maybe only 30% of autistic children are put in ABA programs, about 70% seem to undergo speech therapy, which is also pretty expensive. I won't dispute the $29,000 a year figure, but let's see what the lifetime cost might be. How many years are autistic children put through these therapies in average? Let's say 5 years. This gives a lifetime cost of $145,000.

I won't consider expenditures in quackery, as this is not a cost of autism, but a cost of ignorance.

The author also considers indirect costs:

Indirect costs equal the value of lost productivity resulting from a person having autism, for example, the difference in potential income between someone with autism and someone without. It also captures the value of lost productivity for an autistic person's parents. Examples include loss of income due to reduced work hours or not working altogether. Ganz estimates that annual indirect costs for autistic individuals and their parents range from more than $39,000 to nearly $130,000.


The average annual income per person in the U.S. is about $30,000, so right there the figures provided in the article do not make sense.

It appears that about 25% of autistic people diagnosed a generation back work and live independently. But the analysis is about autistic people diagnosed today under current criteria. Let me make an assumption here. About 25% happens to be the percentage of autistic people evaluated as not having mental retardation a generation back. Currently, that's more like 70%. I conclude that about 70% of autistics diagnosed today will live independently and work. (No, I'm not saying that only those without mental retardation work, or that none of those without mental retardation are out of a job -- I'm just using this as an artifact to estimate trends). So if we were to assume that the average income of a working autistic person is equivalent to the population average, annual wages lost per autistic person would be $9,000 a year. But that is a big if. Autistics might tend to have very low wage jobs. On the other hand, they might tend to have very technical jobs which are fairly well paid. Either way, let's assume $9,000 x 40 is lost in wages per autistic person over a lifetime, or $360,000.

There are intangibles which aren't taken into account. How do we quantify the contributions of someone like Temple Grandin to the food industry? Or the contributions of Vernon Smith to, you know, ECONOMICS. Are we allowed to claim Bill Gates? His net worth is $53 billion, a tad more than the purported annual cost of all autistics in the U.S.

What I've estimated so far comes to a lifetime excess cost of $542,300 (minus big intangibles) per person. I do not believe it is anywhere near $3.2 million. Trouble is, a figure that is not in the millions won't make for big headlines.

Monday, November 20, 2006

The Verstraeten et al. Gambit

It is common knowledge by now that proponents of the link between thimerosal containing vaccines and autism have been left without any epidemiology to speak of. This is because the credibility of the two and only researchers involved in trying to demonstrate an epidemiological link between TCVs and autism, Mark and David Geier, has taken a substantial hit, due to the work Kathleen Seidel has single-handedly done to expose dubious activities related to the Lupron Protocol.

As a result, it appears that an old talking point of mercury militants has acquired renewed importance. Roughly, they claim that an early draft of Verstraeten et al. (2003), which I'll refer to as Verstraeten et al. (2000), showed there was a link between thimerosal and autism, but this link was later covered up by the CDC. It's of interest to note that Verstraeten et al. (2000) is the same draft that was plagiarized by Geier & Geier. (No need to dance around the word plagiarism, as such is patently obvious).

In order to verify the claims about Verstraeten et al. (2000) I decided to, you know, go and read the draft. Let's analyze the various claims.

Is it true that Verstraeten et al. (2000) showed there was a link between autism and thimerosal?

Simply put, no. The abstract does not mention autism. To see why that is the reader should look at relative risks for various outcomes after exceeding EPA mercury exposure guidelines at 1 and 3 months of age in Table 4. The relative risks for autism are 1.01 (CI 0.71, 1.48) and 0.94 (CI 0.62, 1.42). In other words, the relative risks found happen to be very close to 1.0 and the range of statistical confidence is broad around 1.0.

It's pretty astonishing that many people have claimed and assumed the draft demonstrated such a link. Let's take, for example, Ginger of the Adventures in Autism blog, who claimed the following:

Verstraten's first draft of the study finds a relative risk above 7 for children who receive the highest dose of thimerosal to develop autism.


What is she talking about? Graph 4 shows relative risks at different exposures. At greater than 62.5 micrograms (by 3 months of age) the relative risk is 1.69. But note that 1.0 is well within the confidence interval. There is no way to conclude a relative risk greater than 1.0 is statistically significant in this case given the sample of 28 children. I will also discuss other reasons why these relative risks can't be taken at face value. Either way, it's not clear where Ginger got the relative risk of 7.

Is it true that Verstraeten et al. (2003) covered up the findings of Verstraeten et al. (2000)?

From the abstract of Verstraeten et al. (2003):

RESULTS: In phase I at HMO A, cumulative exposure at 3 months resulted in a significant positive association with tics (relative risk [RR]: 1.89; 95% confidence interval [CI]: 1.05-3.38). At HMO B, increased risks of language delay were found for cumulative exposure at 3 months (RR: 1.13; 95% CI: 1.01-1.27) and 7 months (RR: 1.07; 95% CI: 1.01-1.13). In phase II at HMO C, no significant associations were found. In no analyses were significant increased risks found for autism or attention-deficit disorder.


These results appear to be similar to some of those in the early draft. The difference is that the 2003 study includes additional HMOs. But maybe Verstraeten et al. are pretty bad at covering up data.

There's a whole mythology of conspiracy surrounding Verstraeten, the VSD and, you guessed it, the Geiers. See Kev's post titled Mark Geier, David Geier and the VSD.

What about the risk ratios for outcomes other than autism?

That autism is not involved doesn't mean I will just ignore the rest of the findings. The early draft does find statistically significant risk ratios for several outcomes. But is there good reason to take these ratios at face value?

Those familiar with vaccine safety studies generally understand that VSD is a much more solid database than VAERS. That is, you can't literally plant data in VSD, and VSD is not likely affected by prevailing causation hype or the interests of litigants. This, however, doesn't mean VSD is impervious to confounds beyond random error. VSD still records outcomes based on existing diagnoses, not the results of whole population screenings. In a cohort of children expanding many years, recent diagnoses are not necessarily equivalent to older diagnoses. Surely, things like coincidental trends and left censorship could have an impact on any findings.

After looking at graphs in the 2000 draft, I came across a number of peculiar results. I will list some examples, so the reader can get a clear idea of whether risk ratios from the draft can be taken at face value.

In Graph 1 we find that if you inject children with more than 62.5 micrograms of mercury by 3 months of age, their risk of developing degenerative neurological disorders is only 40% of what it would be otherwise. And this is a statistically significant finding. In Graph 3 we find something similar about renal disorders. Apparently mercury is good for your kidneys. Graph 15 says about the same about infantile cerebral palsy. In other words, thimerosal prevents brain damage.

Graph 8 shows that risk for sleeping disorders increases by a factor of 1.75 with a exposure of 50 micrograms. The solution? Inject more thimerosal. Apparently with a exposure over 62.5 micrograms, the risk drops back down to 1.09.

Graph 13 tells us that the risk of developmental speech disorder is only 0.59 at 25 micrograms of exposure, even though the risk is between 1.25 and 1.47 at higher exposures. I guess you have to be careful to choose the right dose if you want to prevent almost half the cases.

Graph 20 is the most peculiar of all. It tells us that premature infants would have about a fifth of their normal risk of developing neurological disorders if only they are injected with 50 micrograms of thimerosal. And this finding is quite statistically significant, as the sample sizes in this graph are considerably larger than in other graphs.

It is clear that it would've been irresponsible for Verstraeten et al. to just publish these findings without clearly outlining limitations and potential confounds. This is not only because of the anti-vaccination scare that would result, obviously. So maybe they did think about that and that's why they decided to look at more HMOs. Which is a good thing.

Thursday, November 09, 2006

What Is Neurodiversity?

There is a new Yahoo! group titled What Is Neurodiversity?. Its stated purpose is the following:

The purpose of this group is simple - to discuss what is and what isn't neurodiversity. There are no formal principles or rules but there is a lot of (mis)information about what neurodiversity is and what it means on a realistic basis as well as a principled basis. Hopefully this Group will serve to set the record straight.


Trolls (yes, we all know who you are) are not welcome.

Friday, November 03, 2006

Is the TV Hypothesis More Plausible than the Thimerosal Hypothesis?

This is sure to rattle some sensitivities, but that's just too bad. It is on record that I consider the TV hypothesis to be almost certainly false (see my analysis and additional critiques in the comments section). This, nevertheless, does not preclude me from contrasting and comparing this hypothesis with any other hypothesis on their merits.

I have been accused of all sorts of things for doing this. One commenter (Erik) even insinuated I must be in the pockets of the CDC or Big Pharma. The same insinuation has been made about the Cornell researchers who did the TV study, and I have seen that in several blogs and mailing lists. What is the scenario here? Are we to believe that the CDC had a meeting where they decided to pay a group of economists to conduct an epidemiological study involving cable subscriptions and annual precipitation rates? Right! "Shhh... just don't tell anyone Mr. Economist." BTW, did any whistleblowers come forward yet?

This type of conspiracist paranoia is suggestive of something. It is apparent that to many the TV hypothesis is not a laughing stock, but actually very serious business. Its impact has been significant among the more anti-vaccination elements of the community. Hundreds of messages have been posted to the EOHarm mailing list about this study, many of them very angry messages. The researchers have been harassed by email, and probably even by phone. (See Kev's post on the subject).

Well, thimerosal hypothesis proponents should be worried. Here are the areas in which I believe the TV hypothesis is actually more sound and plausible than the thimerosal hypothesis:

  1. Time Trends.- In the last several decades, there is only one period of time when thimerosal exposure increased consistently and significantly in the US. That is the period between the birth years 1990 and 1994. At other times, thimerosal exposure has been either fairly stable or declining. In contrast, the administrative incidence of autism has been on a smooth upward trend for several decades, most notably in the 1990s. Roughly the same could be said of TV exposure.

  2. Regional Epidemiology.- No regional epidemiology exists involving thimerosal and autism, nor is it likely the thimerosal hypothesis could explain both a significant rise in autism incidence over time and the considerable differences in autism prevalence across states and counties. In contrast, the TV study presents a per-county analysis across several states for both cable subscription rates and precipitation rates. The cable subscription analysis even adjusts for time-independent per-county effects.

  3. Credibility of Researchers.- The only thimerosal epidemiology which can be found in the scientific literature has been authored by Mark and David Geier. The scientific conduct of these researchers has come under fire recently amid allegations of affiliation misrepresentation, IRB irregularities, use of dual terminology, misrepresentation and alteration of cited work, apparent plagiarism and use of salami publications, potential breaches of confidentiality, unreproducibility of results, omission of data, a suspect "order of magnitude" error, conspirationism and fear mongering, and assorted fabrications. Their conflicts of interest include having filed a patent application for their "Lupron Protocol", and, astonishingly, a connection to a pharmaceutical company. A quick search reveals nothing comparable about Waldman et al.

  4. Extent of Exposure.- The peak thimerosal exposure in the US from all vaccines combined was about 180 micrograms (in 1994). Each vaccine contained as much as 25 micrograms of thimerosal. A conservative estimate (by Sallie Bernard, no less) suggests an average tuna sandwich contains 12 micrograms of methylmercury. However, if we consider that 6 oz. of albacore tuna has 60 micrograms of methylmercury, a tuna sandwich could have over 30 micrograms. Either way, TV exposure appears more significant. Autistic children can watch TV for hours a time, day after day, sometimes asking to watch the same DVD over and over again.

  5. Strengths & Impairments.- From the very beginning autistic people were described as having areas of strength and impairment. It seems difficult to come up with a model by which brain poisoning would result in cognitive strengths. But it is not impossible to imagine how television might cause certain impairments over time while enhancing other areas of perceptual functioning.

  6. Removal of Thimerosal.- Thimerosal is considered to have been largely removed from vaccines in the US territory by 2001. But it has been removed in other countries too. It was removed in Sweden and Denmark in 1993. It was removed in Canada in 1996. It was removed in the UK (not sure about the year). Yet, no country has ever reported a decline in the incidence of autism, not even anecdotally. No one has ever said, "hey, wait a minute, there are less little ones with autism now" (well, actually, I know a pair of characters who have claimed just that). The TV hypothesis doesn't have something so obviously damning against it (yet).

  7. Anecdotal Evidence.- It's early to draw a controlled comparison, but I'll quote something from Jennifer: "By the way, my child did regress at about the same time as she became very interested in watching TV. I've wonderered for years if it wasn't a factor in her gradual social withdrawl. I was so interested that I set up a survey. I asked parents if they had found various therapies helpful (or not). One of the questions was about 'Cutting back on television/video watching'. That received 24 favorable votes, compared to 4 unfavorable, which compared quite respectably to the top therapies which were speech/language therapy which received 38 votes for and 4 votes against, and ABA which received 31 votes for and 3 votes against. Chelation was much less favored, with only 6 postive, and no negative votes."


Are there areas in which the thimerosal hypothesis looks better than the TV hypothesis? Maybe. But I'll just let readers comment on those.

Monday, October 30, 2006

Autistic Teens Being Taught They Are "Recovered"

Thanks largely to the magic of YouTube, it's now possible to see what people mean when they claim that autistic children have "recovered" from autism. There are several videos with such children which can be found in YouTube. I'll post a couple here, without naming any names.





What do readers think? Obviously autistic teens are being taught essentially that it's bad to be autistic but they shouldn't worry about it because they are "recovered" now. Is this good, bad or indifferent, considering these teens are probably able to pass (with an unknown amount of effort)?

In a letter to BMJ, a psychiatrist named Sami Timimi provides an anecdotal account of autistic teens asking to be undiagnosed:

In my clinical practice I often come across children and adolescents who are labelled autistic. When I focus on their abilities I often find much about them that does not fit the autistic discourse. Once I reopen the question of diagnosis many adolescents ask me to officially "undiagnose" them, which their parents are usually very pleased about.


I can see why a teenager might not want the "autistic" label. And it's not surprising that most parents would be pleased, even though the child is the same child before and after the label is removed. But there's obviously something wrong with this, in a social sense.

Wednesday, October 25, 2006

An Island of Rationality

The following was overheard in EOHarm recently:

However, unless mercury is somehow being slipped into children in greater amounts now than in the 90's, mercury does not seem to be the main cause of autism now. And no, I don't think the mercury in the flu shots is capable of offsetting the mercury infants got at birth, 2, 4 and 6 months in the 90's. Flu shots present smaller doses at later ages, and the big flu shot push for kids didn't get started until 2004 anyway.


The message has not had any replies, and it's not clear if the person who posted is still in the list after such a blasphemous remark.

This was written by someone who does believe vaccines have "almost everything to do" with autism. But this person does take the time to look at the actual CDDS numbers and not just claims about the numbers, and clearly has some skills that allow her to interpret the numbers. For her critical thinking, she should be commended.

I should note that she claims to believe in the work of the Geiers, which is actually inconsistent with her analysis of the CDDS numbers.

She expresses concern about the "57% increase in the 3-5 year olds" (in the last 4 years). And makes a good case about prevalence, which follows.

Let's assume the 1 in 166 for ASD (which includes Asperger's and PDD_NOS, not included in these numbers) is going to be close to what you would get based on people that were 3 to 21 in 2002. The US Census Bureaus says that California has approximately 500,000 people of each age in the younger ages – or 57,200 people with ASD. The 2002 full autism numbers for ages 3 to 21 add up to 15,939, or about 27.9% of the ASD population and also about 1 in 600 for the entire age cohort. The 2006 group of 3-5 year olds represents 0.41% of the California population age 3-5. If you assume these number will increase 62% in the next 4 years, as did the 3-5 group from 2002, you get 0.67% of the population, or 1 in 150 -- FOUR TIMES THE CURRENTLY REPORTED RATE!!!


I do also share her concern that the current prevalence of 40 in 10,000 for the 3-5 cohort is higher than expected for Autistic Disorder, and this prevalence is still growing at a fast pace. That is, it's not clear when it will level off, and we can't assume there's a magic number it cannot go over. But it's not as bad as she thinks. Anecdotally, some PDD-NOS and Asperger's does get included in the CDDS numbers. Besides, in psychology there's a debate about the existence of Asperger's. Some researchers are saying that DSM-IV Asperger's is impossible to diagnose, and that virtually all children diagnosed with Asperger's actually have Autistic Disorder. If this opinion becomes mainstreamed, what do you think the end result might be in terms of caseload?

Additionally, it's unlikely that the 62% increase will be maintained over the next 4 years. Growth expressed as a percentage necessarily decreases over time.

She adds:

We really [need] to get to the bottom of this. The effects on society are almost too big to contemplate.


The fact that more and more children are being labeled with all sorts of cognitive disorders is a valid concern, in my opinion. Sami Timimi, for example, is an outspoken critic of psychiatric over-labeling. He says that we'll end up with a generation of grown-up children who have been unnecessarily convinced that they are defective. But should we be concerned about an increasing number of people becoming disabled? I think we should be really concerned about this if, say, the prevalence of institutionalized developmentally disabled individuals were increasing. (However you look at it, more institutionalization is not a good thing). But it's not increasing. In fact, it has dropped a little in the last 14 years in California, according to the CDDS numbers. If our concerns are not consistent with reality, what is the use of our advocacy?

Saturday, October 21, 2006

Precipitation Rates vs. Population Density in Pennsylvania

Criticism of the autism-TV study out of Cornell has so far focused on the perceived plausibility of the hypothesis, and on author credentials, for the most part. For example, it has been pointed out that autism is present since birth/conception (or acquired in utero). If only it were that easy to dismiss post-natal environmental trigger theories these days.

The study was thought to be a prank at first, due to its peculiar methodology, but it's clear by now that it is not meant as a joke. Apparently, a lot of work went into it.

The authors of the study are economists, and this seems to be taken by many as a quick way to dismiss the study altogether. I would note that they are not the first authors of an epidemiological study on autism who are not trained in autism epidemiology. I think the study needs to be considered and critiqued on its merits.

Alternative interpretations have been proposed. Perhaps humidity causes autism, through mold and mildew, for example. Maybe spending time outdoors is a preventive measure. And so forth. These alternative interpretations, nonetheless, simply switch one hypothesis with another of equally unknown plausibility.

What I'd like to do in this post is propose an interpretation of the results based on a hypothesis known to be plausible, and which has been documented previously. Namely, that the results can be explained by a established correlation between degree of urbanization (or population density) with the administrative prevalence of autism. I already did something similar in a critique of the environmental pollution hypothesis.

That cable subscription rates are correlated with degree of urbanization or population density is a sure bet, and I won't consider that further. A potential correlation between population density and annual precipitation is non-obvious, however, although I had previously suggested that people generally don't build communities in the dessert.

I will use the state of Pennsylvania for this post, simply because there's readily available data on administrative prevalence with high regional granularity from that state. The authors analyze California, Oregon and Washington for precipitation. Readers can check if the analysis holds in those states. Fortunately, I didn't have to do much work to get the data I'm about to present, save for a few Google Image searches. Let me first post images modeling annual precipitation in the state of Pennsylvania.


Figure 1. Annual precipitation in Pennsylvania
(found at usda.gov)



Figure 2. Annual precipitation in Pennsylvania
(found at orst.edu)


Now, let me post an image with modeling of population density, and an image which shows the location of major cities in the state of Pennsylvania.


Figure 3. Population density of Pennsylvania counties
(found at dep.state.pa.us)



Figure 4. Pennsylvania road system, showing major cities
(found at smart-traveler.info)


Already we can see there is a fairly clear correlation between precipitation and population density in part of the state, perhaps even in 2/3rds of the state taken from East to West. Such a correlation is not at all clear in the West side of the state, but the correlation in the East side is probably enough of a confound.

Let me now post an image modeling autism prevalence across the state of Pennsylvania.


Figure 5. Pennsylvania IDEA autism cases per 10K enrolled
(found at fightingautism.org)


A correlation with either population density or precipitation is not that clear at first glance, is it? Let's focus on the bluest patches of prevalence, and let's compare with the Pennsylvania road map. You will note that high prevalence tends to coincide with urban areas, namely, Philadelphia, Harrisburg and Pittsburgh. Pittsburgh is particularly interesting, because it's an area with low precipitation. That's on the West side of the state, where I noted that a correlation between precipitation and population density was not clear.

Admittedly, there is an area near Erie (North-West corner) where there is high precipitation and high autism prevalence, but population density does not seem to be exactly where you would expect. This data point throws off my argument a bit, but it's not much to go on.

Going forward

The correlation between administrative prevalence of autism and population density lends itself to false correlations between autism rates and innumerable proposed contributing factors in autism. It would be extremely easy, for example, to "prove" the autism fries hypothesis using this type of analysis. In the future, regions with equivalent population density and wealth should be compared. Additionally, studies should be devised to determine if differences in autism prevalence between regions are actual or simply administrative.

Note: I plan to email Dr. Waldman and refer him to this post.

Addendum

I thought I would share a couple of remarkable images modeling annual precipitation and population density in the United States.


Figure 6. Annual precipitation in the U.S.
(found at ncgc.nrcs.usda.gov)



Figure 7. Population density in the U.S.
(found at wikimedia.org)


If you've ever wondered why population in the U.S. distributes the way it does, here's a big part of the answer. I have noticed that it's not so much that precipitation positively correlates with high population density, but that lack of precipitation correlates rather well with low population density. This is fairly obvious in retrospect.

Friday, October 20, 2006

Neurodiversity Trying to Steal "Autism" from the Disabled

Michelle Dawson and Laurent Mottron recently participated in an excellent radio segment titled Rethinking Autism in a CBC radio show called Quirks and Quarks. In it they discussed a new model of autism as a type of person, in contrast to the prevailing model of autism as a broken normal person.

Lenny Schafer, posting on Tue Oct 17, 2006, in the mailing list EOHarm, reacted to the program as follows:

The neuro diversity campaigners continue their efforts to redefine autism as not a disability, but a personality trait we just all need to learn to live with. This is nothing more than the crass exploitation of the disabled and needs to be called out as such. They are trying to steal "autism" from the disabled.


My first reaction to this was to think that Lenny Schafer is trying to steal "semantics" from grammar. No, seriously, I'm not sure I understand what he's trying to say.

Maybe he is saying that all anti-cure autistics are not disabled, but all pro-cure autistics are disabled? And that we are trying to steal the "autism" label from pro-cure autistics?

Or perhaps he thinks the autism rights movement is at odds with the disability rights movement? Is it? I wonder what deaf people think of autism rights, for example.

Friday, October 13, 2006

CDDS Q3 2006: Thimerosal Hypothesis Still Dead

Background

Back in November, 2005, David Kirby agreed with blogger Citizen Cain on the following:

If the total number of 3-5 year olds in the California DDS system has not declined by 2007, that would deal a severe blow to the autism-thimerosal hypothesis.


Let me emphasize that David Kirby also conceded that what matters is the total number of 3-5 year-olds, not changes in caseload growth. As I have argued, drops in caseload growth should be expected in the long run anyway.

Data

With one quarter to go before 2007, the latest quarterly report is out, as first blogged by Dad of Cameron. Please check out his graph of the 3-5 cohort caseload for the last 17 quarters.

Here's a table with some of the highlights from the last 4 quarters.

Table 1: State-wide comparison of Q3 2006 with three prior quarters.
QuarterCaseloadGrowth
(False New Cases)
Annual Growth (%)3-5 Cohort
Q4 200529,42470010.72%5,680
Q1 200630,18175710.50%5,827
Q2 200631,01283110.56%6,083
Q3 200631,85384110.89%6,188


The key information in Table 1 is that the 3-5 caseload continues to grow, and this growth is still rather fast compared to population growth in the state of California. Barring any miracles, in one quarter David Kirby will either need to issue a statement saying that he no longer believes in the autism-thimerosal hypothesis, further goalpost-shift the target date for a caseload drop, or claim that there hasn't really been a significant drop in the thimerosal dose per child in California. What do readers predict he will do?

It's a bit surprising that caseload growth has increased for at least the last 4 quarters in a row. Even when expressed as an annual percentage, it seems to be in an upward trend. As I've noted before, this might indicate that leveling off of the population (i.e. annual caseload growth matching California population growth of about 1%) is still very far away.

CDDS autism prevalence for the 3-5 cohort is currently about 40 in 10,000. This is not supposed to include PDD-NOS or Asperger's, but anecdotally it is known that diagnoses are changed in order to force eligibility in some cases.

Thimerosal Hypothesis

It is important to understand what the "thimerosal hypothesis" is. Versions vary slightly, but let's take Mark Blaxill's one, as presented to the IOM in 2001. Blaxill indicated that mercury exposure from vaccines went from about 70 micrograms for the 1991 birth year cohort to about 180 micrograms for the 1994 birth year cohort, which coincided with an increase in the prevalence of autism for birth year cohorts between those years. That is, most or all of the prevalence increase during the "autism epidemic" of the 1990s can be attributed to an increase of the thimerosal dose per child, according to Blaxill.

Were Blaxill's hypothesis correct, if thimerosal exposure drops to levels below 70 micrograms, the 1990s epidemic of autism should be reversed. Even if you believe there are still traces of thimerosal in vaccines, and that children are still exposed to 25 micrograms of thimerosal from the Flu vaccine, it is clear that thimerosal exposure is no more than it was in 1991 and the entire 1970s and 1980s for that matter.

Note that the 3-5 CDDS autism caseload in Q2 1992 was 462. That is about 13 times less than what it is today. There is no denying such clear numbers. The only way to continue to believe in a hypothesis such as Blaxill's involves suspending reason. At this point we are simply waiting for the main proponents to come clean on that, provided intellectual honesty means something to them.

Wednesday, October 11, 2006

Coming Out Day Video



This video is about human rights from the gay rights movement's perspective. But I'm sure many readers will find it applicable.

Tuesday, September 26, 2006

A Plausible "Epidemic" Hypothesis

I have argued many times that there hasn't been a real epidemic of autism. The evidence is compelling. For example, we know how much the proportion of autistic CDDS clients with mental retardation has changed since 1992 to the present time. We know that the rate of institutionalization of developmentally disabled individuals is not on an upward trend. And there is evidence of diagnostic substitution. But we are still left with the question as to why the number of diagnoses has increased so much.

Sure, we talk about an increase in awareness and changes in criteria and cultural perceptions. But why did this happen mostly in the 1990s? Lorna Wing coined the term Asperger's syndrome in 1981. The DSM-IV was published in 1994, years after the increasing trend in diagnosed cases had started. The trend accelerated after the DSM-IV publication, but there's no noticeable spike. I think there has to be an independent cultural phenomenon that drove changes in awareness and cultural perceptions.



I think the key to answering this question comes from parent experiences regarding how a child's diagnosis of autism came about. Usually it goes like this. The pediatrician tells the parents not to worry or gives an assessment completely unrelated to autism. The parents start to do their own research. Then they go to a hospital or find an specialist who is able to diagnose autism. My guess is that when parents visit a psychiatrist they typically already suspect the diagnosis of autism.

It is not far fetched to suppose that the internet has made a huge difference in providing parents the ability to carry out extensive research, and enhancing general awareness.

The internet began to take off shortly before the 1990s. At that time there was Usenet. There were mailing lists. It was more of an academic tool rather than a corporate one. Gopher was released in 1991 and begun to gain in popularity. By Q2 1994, the world wide web surpassed Gopher and that's when the internet really exploded.

Growth in number of internet hosts


What the hypothesis predicts

  • Regions with higher internet penetration will tend to have a higher incidence of autism. (This would explain in part the link to degree of urbanization, with another factor being availability of specialists).

  • In populations with no internet access whatsoever, autism will be virtually unheard of.

  • At time of diagnosis, households with an autistic child are more likely to have internet service than households of a control group matched by age, even after social class is considered.

  • Internet access correlates with reduced elapsed time from concern to diagnosis.

Wednesday, September 20, 2006

Breastfeeding and EFAs

I just found this study in PubMed and I was surprised that no one has commented yet. Maybe it just appeared there. I think this could be pretty controversial.

Breastfeeding, Infant Formula Supplementation, and Autistic Disorder: the Results of a Parent Survey.

Schultz ST, Klonoff-Cohen HS, Wingard DL, Akshoomoff NA, Macera CA, Ji M, Bacher C.

ABSTRACT: BACKGROUND: Although autistic disorder is associated with several congenital conditions, the cause for most cases is unknown. The present study was undertaken to determine whether breastfeeding or the use of infant formula supplemented with docosahexaenoic acid and arachidonic acid is associated with autistic disorder. The hypothesis is that breastfeeding and use of infant formula supplemented with docosahexaenoic acid/arachidonic acid are protective for autistic disorder. METHODS: This is a case-control study using data from the Autism Internet Research Survey, an online parental survey conducted from February to April 2005 with results for 861 children with autistic disorder and 123 control children. The analyses were performed using logistic regression. RESULTS: Absence of breastfeeding when compared to breastfeeding for more than six months was significantly associated with an increase in the odds of having autistic disorder when all cases were considered (OR 2.48, 95% CI 1.42, 4.35) and after limiting cases to children with regression in development (OR 1.95, 95% CI 1.01, 3.78). Use of infant formula without docosahexaenoic acid and arachidonic acid supplementation versus exclusive breastfeeding was associated with a significant increase in the odds of autistic disorder when all cases were considered (OR 4.41, 95% CI 1.24, 15.7) and after limiting cases to children with regression in development (OR 12.96, 95% CI 1.27, 132). CONCLUSIONS: The results of this preliminary study indicate that children who were not breastfed or were fed infant formula without docosahexaenoic acid/arachidonic acid supplementation were significantly more likely to have autistic disorder.


The methodology looks OK. For anyone interested in environmental factors in autism, there you go. Nutrition and brain development appear to be related (no kidding). It even looks like there's a stronger correlation of lack of EFA supplementation to regressive autism.

This puts a recent double-blind study of EFAs in perspective. So for anyone interested in "biomed" interventions, there you go.

There are prior studies on lactation supplementation and neurological outcomes in the general population. See, for example, Birch et al. (1999) and Helland et al. (2003).

I would not say that reduced EFA supplementation causes autism, but it probably makes a diagnosis more likely.

Tuesday, September 12, 2006

MZ Twin Discordance

The autism twin study considered the best methodologically speaking found a MZ twin concordance of 60% for autistic disorder and 92% for a broad spectrum. The DZ twin concordances were 0% and 10% respectively. Given that MZ twin concordance is not 100%, people correctly assume that environmental factors must be involved in the etiology of autism. But some go further than that and speculate that the environmental factors must surely be environmental "insults", and that they probably occur post-natally.

This would probably be true if there was no random variation in brain development, and no phenotypical variability due to the social environment. No human phenotype is 100% heritable. Only very simple physical phenotypes, such as eye color, approach that level of concordance.

Let's take White et al. (2002). This study compared the brains of general population MZ twins and found a concordance of over 0.90 for white and grey matter volumes, but only 0.75 for the thalamus, to take one example.

Syndromes known to be genetic in nature can have discordant expression. Kruyer et al. (1994) reports on two sets of MZ twins discordant for Fragile-X. In one pair of sisters, one has mental retardation and the other does not. In each of the pairs the researchers explained the discordance genetically. A Google Scholar search on discordant MZ twins reveals many other such reports.

MZ twins can be discordant for homosexuality. But there is no significant effort to try to pin down the environmental factors involved there. (Hint: It's not likely the vaccines).

Concordance of intelligence is not 100%. It seems to be about 80% for MZ twins reared together, and slightly lower for MZ twins reared apart. Phenotypical variation for intelligence is probably determined by the neurological variability discussed above, plus life experience.

The social environment should not be discounted altogether, as much as people would prefer to. A case in point is that of congenitally blind children, who tend to become autistic.

For those who believe ABA (or some other treatment) works, here's something to ponder. Imagine a pair of autistic MZ twins, one given to a family that believes in ABA and the other given to a family which does not. Can the subsequent discordance be blamed on the one set of parents?

Note that I'm not saying that autistic children are never subject to environmental insult, or that environmental insult does not result in autism-related phenotypical variability. I am simply saying that environmental insult is not necessary to explain MZ twin discordance, as is often argued.

Saturday, September 09, 2006

Dan Olmstead's New Pet Theory

It's no secret that many proponents of now discredited hypotheses are quietly pursuing new causation theories without explicitly admitting so. But more than pursing new causation theories in an effort to improve our understanding of autism, they seem intent in continuing to look exclusively for "something wicked."

Dan Olmstead, a journalist of "no autism among the Amish" fame, is a case in point, with his three new Age of Autism articles titled Something Wicked -- 1, Something Wicked -- 2 and About Those "Old Dads". In them he puts forth the hypothesis that autism may be caused by chemicals parents are exposed to. The mechanism or its plausibility are not clear, but let's leave that aside for the time being.

Olmstead cites work by Thomas Felicetti, who had found a higher prevalence of chemists among the parents of autistic children compared to controls. This confirmed prior work by Mary Coleman. He further goes into the case histories of Kanner's 11 autistic patients born in the 1930s. Let me quote from his "Old Dads" article:

We've also pointed out a possible connection in the very first cases described in the medical literature -- 11 children born in the 1930s -- with new chemical compounds, plausibly including mercury-based fungicides. One of those 11 kids was the son of a plant pathologist, another the son of a forestry professor at a southern university, and a third grew up in an area being heavily planted with seedlings to create a national forest in Mississippi (there's that southern forestry connection again -- in fact, his home town is named Forest).

A fourth was the son of a mining engineer. And the very first case to come to medical attention, at Johns Hopkins University in 1935, was the son of a 30-year-old chemist-attorney at the U.S. Patent Office. A chemist.


Anyone with more than a passing interest in autism research will recognize the obvious confound in this hypothesis. I would also point out that these studies are from a different generation, and we might find things have changed. For example, I would wager computing might be a relatively common occupation among parents of autistic children nowadays. (Readers are encouraged to provide anecdotal data in the comments section).

A series of articles (e.g. Baron-Cohen et al. (1998)) have shown that mathematicians, computer scientists, physicists and engineers are over-represented among the parents of autistic children. Jarrold & Routh (1998) analyzed the data and found that the parents of autistic children were also over-represented in accountancy and science, suggesting that perhaps there's a general professional over-representation. Wheelwright & Baron-Cohen (2001) argued that even taking into account a possible over-representation of professionals, engineers were still over-represented.

Further evidence of this confound comes from an AQ test assessment by Baron-Cohen et al. (2004). The researchers found that "scientists (including mathematicians) scored significantly higher than both humanities and social sciences students" and that "within the sciences, mathematicians scored highest." Further, the group of Mathematics Olympiad winners scored significantly higher than the male Cambridge Humanities students.

Dan Olmstead does try to address the confound by pointing out that there is no correlation between social class and autism, which is correct. But social class is clearly not what the confound is about.

Monday, September 04, 2006

More About Mark Blaxill

In a presentation to the IOM (July 16, 2001), Mark Blaxill showed the following graph of cumulative mercury exposure (thimerosal dose per child) and the administrative prevalence of autism by birth year cohort:



Blaxill's graph was also shown in Figure 1 of Stehr-Green et al. (2003). Stehr-Green et al. conclude that there is no consistent relationship between thimerosal and autism, however. The graph also has some similarities to Figure 2 of Geier & Geier (2004) which I already critiqued. The drop in prevalence and thimerosal exposure starts one year earlier in the Geiers' paper.

The thimerosal dose per child in the graph is probably correct. The main problem with the graph is that it shows a prevalence drop in the 1995 birth year cohort. This drop is likely due to left-censorship. In other words, children in recent birth-year cohorts are too young to be diagnosed. Graphs by birth year cohort are not fixed. They change as they are revised from one year to the next. The prevalence of autism did not really drop for people born in 1995 and 1996. So the correlation shown there is either a coincidence or you would have to wait for the right year to make the graph.

In fact, a 2005 SafeMinds document by Redwood and Blaxill has a graph (second one down) which clearly shows the prevalence by birth year cohort did not drop in 1995, 1996 or 1997.

The graph from Blaxill's 2001 presentation says children were surveyed 2 years after their birth year. But this simply cannot be right. If you look at the 2005 SafeMinds document, it is clear that prevalence in a birth year cohort stabilizes at about age 8 and it's about half its peak at age 3. The 2001 graph is close to the 2005 graph, except for the 1995 birth year prevalence. The 2001 graph appears to simply show prevalence by birth year cohort, as surveyed around the year 2000.

Another problem with the graph is that it doesn't show thimerosal exposure before 1989. If it did, it would likely show a flat bar graph before that year, concurrent with an increasing autism prevalence trend. In other words, graphing thimerosal dose per child before 1989 would tend not to support the desired correlation. Geier & Geier (2004) avoids that problem by simply skipping the 1986-1989 range altogether in their graph.

Methodological problems aside, Mark Blaxill is known as a reasonable and knowledgeable individual. He clearly knows about thimerosal dosage and about autism prevalence. He must realize that birth cohorts after 2000 could not have received more than 25 micrograms of thimerosal – less than 1/3rd of what he shows for 1989. He must also realize autism prevalence is not dropping in the youngest age cohorts data is available for. As Mark Blaxill is respected by proponents of the thimerosal hypothesis, isn't he the most indicated person to put this hypothesis to rest? I think history is calling upon Mark Blaxill to do the right thing. Why is he so quiet about this nowadays?

Friday, September 01, 2006

Talking Back to Mark Blaxill

Some pretty interesting events seem to be unfolding at EOHarm these days. But in this short post I just want to address two statements I found Mark Blaxill has made there, and I would like to invite him to debate the first one.

The best estimate for the number of children (aged 4-17) with ASD is about 300,000. That means the total US population, including adults, is unlikely to be over 400,000. (Aug 4, 2006)

If Mark Blaxill believes that ASD is rare in adults, I hope he can address Stahlberg et al (2004), Shah et al (1982), Baron-Cohen et al (2001) and Wakabayashi et al (2004). Or perhaps Mr. Blaxill just means "diagnosed" ASD, in which case he might be right, but that would mean he has given up his "hidden horde" device. If he meant "autistic disorder" and not ASD as he stated, that's a little bit harder to judge given available data, but his numbers would also be wrong.

Another one:

This is an excellent critique. More than adding new reviews, a simpler step is for EVERYONE here to go to amazon, search for Offit's book and the RATE THE REVIEWS!! This is easy to do. There is a voting button where you can say yes or no to the question, "Was this review helpful to you?" (Dec 30, 2005)

Here I just want to point out that Autism Hub readers can also go to Amazon, look for any book (e.g. "Evidence Of Harm"), rate the reviews, and add your own review – if you have read the book of course.

Thursday, August 31, 2006

My Turn at the Book Meme

I've been tagged by Abfh. Let's see...

One book that changed my life

I'd have to go with a book I don't have anymore and don't remember the title of. It was a BASIC programming manual of some kind I read and referenced many times when I was a young teenager. That was many years before Intel-based PCs became widely available. I remember distinctly that the BASIC software available in the 16K-RAM computer I played with at the time was made by Microsoft, though – likely coded by Bill Gates himself.

One book that you've read more than once

Hmm... I'm not sure I've ever done that.

One book you'd want on a desert island

Obviously, something such as "SAS Survival Handbook: How to Survive in the Wild, in Any Climate, on Land or at Sea".

One book that made you laugh

There are many. One that comes to mind is "Seinlanguage" by Jerry Seinfeld. It's basically a compilation of all his usual observational comedy, but it was a funny read.

One book that made you cry

Pass.

One book you wish you had written

I'll name several. "A Brief History of Time" by Stephen Hawking. "Cosmos" by Carl Sagan. And "The Selfish Gene" by Richard Dawkins.

One book you wish had never been written

I can think of at least a couple. I'll say "Evidence of Harm", not because it hurts a political stance, but because it's a waste of good paper and people's time.

One book you're currently reading

I'm in between books, but a couple weeks ago I finished reading two: "Through the Eyes of Aliens" by Jasmine O'Neill; and "Teaching At Home: A New Approach To Tutoring Children With Autism And Asperger Syndrome" by Olga Holland.

Jasmine O'Neill's book is great and I strongly recommend it. She's not afraid to explain why she experiences autism as a beautiful thing, despite her impairments. That's the kind of thing that should give pause to anyone who compares autism to cancer or AIDS. Jasmine also offers practical advise to parents.

Olga Holland's book is not bad, and offers practical advise, but she clearly does see autism as a disorder that must be defeated and autistic children as defective in some way. Traits of her child she perceives as negative are considered part of his autism; traits perceived as positive are not considered part of his autism. She uses a variation of the "social stories" teaching method throughout the book. In the end she tells how her son tests in the top percentile in some standardized test and enters a gifted program at school. (While being in the top percentile at something is statistically as abnormal as being in the lowest percentile, it is interesting that it is not perceived as such culturally). The author also spends much of her time discussing how horrible communism was in the Soviet Union – which I found to be irrelevant and uninteresting political commentary.

One book you've been meaning to read

"Thinking in Pictures" by Temple Grandin.

People to tag

I'm tagging Not Mercury, Dad of Cameron and Kevin Leitch.

Saturday, August 26, 2006

Why Biomed Will Always Have Little To Show For Itself

With all the hype about MeB12, DMSA, ALA, GFCF, multivitamins and so forth, you might think that there are good reasons to believe these biomed treatments are in some way effective. The reality is that there is not a single biomed treatment for autism that may be deemed clinically proven – not a single one.

And there are some historical embarrassments in the autism biomed field too. I already discussed Secretin, which Bernard Rimland had claimed to have a 75% improvement rate. This was before double-blind studies showed Secretin to be, at best, as effective as placebo. Don't be surprised if the exact same thing happens to DMSA, MeB12 and the others.

Some readers might be thinking that I'm forgetting Vitamin B6, an old but still popular biomed treatment, which does have some placebo-controlled studies under its belt, many of them showing positive results. But note that Nye & Brice (2005) conducted a detailed literature review and concluded that "due to the small number of studies, the methodological quality of studies, and small sample sizes, no recommendation can be advanced regarding the use of B6-Mg as a treatment for autism."

Multivitamins and supplements could arguably be of benefit to overall health, and thus appear to be effective in treating autism. That is how I interpret the results of Adams & Halloway for example. Readers will note that multivitamins in this study were effective in improving sleep difficulties and gastrointestinal symptoms, but had a non-significant effect (compared to placebo) on autistic features such as language, sociability and behavior. If these results are replicated, it would seem that it is a good idea to use multivitamins with children who have sleeping and gastrointestinal problems. This is probably even the case with non-autistic children.

So why is autism so resistant to biomed treatments? Autism biomed is based on a flawed hypothesis. It assumes that autistic children's brains are just about typical, except for a reversible biochemical imbalance or contamination of some kind. Biomed proponents often compare autism to being drunk or stoned. This, of course, is wishful thinking and fails to acknowledge much of what has been found about autistic neurology and cognition.

Autistic brains are different to neurotypical brains. Of course, some will be closer to neurotypical brains than others, but in general, it is known that autistic brains have a different distribution of grey and white matter, different neuron density, neuron size, different overall volume and so on. Autistic cognition is different to neurotypical cognition, with different strengths and weaknesses apparently. I contend that there is very little biomed treatments can do to compensate for these differences and force an autistic brain to work like a neurotypical brain.

The autism community should do better than engage in wishful thinking and waste all this time and resources with biomed. I suggest that autistic children should (1) be educated by engaging their strengths, (2) allowed to exercise their interests, (3) respected for the unique individuals they are, not defective medical puzzles to be solved, and (4) have their true (proven) medical issues, if any, addressed as medical issues, not as part of their very being, which is what autism is.