One of the burning controversies in the autism community is whether or not special diets, specifically gluten-free or casein-free, are of benefit to the symptoms of autism. About 1 in 5 children with autism are on a special diet, and many parents strongly believe it is of benefit, but there has been no scientific evidence to back up their anecdotal observations.

A recent study adds to the evidence for a lack of benefit from such diets. The study is not yet published, but is summarized on the University of Rochester website. The main weakness of the study is that it is small – the study enrolled 22 children and 14 completed the study. It’s strength is that it was tightly controlled. Children were placed on a gluten-free (no wheat and barley) and casein-free (no dairy products) diet for 4 weeks. They were then challenged in a double-blind manner with snacks containing gluten, casein, both, or neither (placebo) and observed for behavior and GI symptoms. The study found no benefit for any outcome measure.

By itself this study is far from definitive and I am sure it will not be the last word. It is a small addition to the growing evidence showing lack of benefit from such special diets in autism.

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I love a good sequel. Aliens, of course, was the best sequel ever – that rare event when the sequel is actually better than the original movie (of course, the series went down hill from there, like Star Trek it peaked with the second movie).

Last year we heard the results of the Autism Omnibus – a special court with three special masters set up to resolve about 5,000 cases before the vaccine court claiming that autism resulted from vaccines – either the MMR vaccine or thimerosal (a mercury-based preservative in some vaccines, but removed from most by 2002). In the US there is a Vaccine Injury Compensation Program (VICP) which bypasses the regular courts and awards compensation to those injured by vaccines, paid for by a small tax on each dose of vaccine given. The purpose is to rapidly compensate those who might have been injured (the threshold for evidence is quite low) and to encourage pharmaceutical companies to manufacture vaccines (the threat of suit would make it not viable otherwise).

Over 2008 the Autism Omnibus heard three cases that were presented as the test cases (presumably the best cases they could come up with) for the theory that the  MMR vaccine (with or without thimerosal from other vaccines – MMR never had thimerosal) caused or contributed to autism in some individuals. They ruled against all three cases, stating in very strong terms that there is no evidence to back up the claims of a link between MMR and autism. Judge Hasting wrote of one case – Cedillo:

Considering all of the evidence, I found that the petitioners have failed to demonstrate that thimerosal-containing vaccines can contribute to causing immune dysfunction, or that the MMR vaccine can contribute to causing either autism or gastrointestinal dysfunction. I further conclude that while Michelle Cedillo has tragically suffered from autism and other severe conditions, the petitioners have also failed to demonstrate that her vaccinations played any role at all in causing those problems.

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This week on Science-Based Medicine I wrote an article about a new study looking at the onset of autism symptoms, showing that most children who will later be diagnosed with autism will show clear signs of autism at 12 months of age, but not 6 months. This is an interesting study that sheds light on the natural course of autism. I also discussed the implications of this study for the claim that autism is caused by vaccines.

Unfortunately, I made a statement that is simply wrong. I wrote:

Many children are diagnosed between the age of 2 and 3, during the height of the childhood vaccine schedule.

First, this was a vague statement – not quantitative, and was sloppily written, giving a different impression from the one I intended. I make these kinds of errors from time to time – that is one of the perils of daily blogging about technical topics, and posting blogs without editorial or peer-review. Most blog readers understand this, and typically I will simply clarify my prose or correct mistakes when they are pointed out.

However, since I often write about topics that interest dedicated ideologues who seek to sow anti-science and confusion, sometimes these errors open the door for the flame warriors. That is what happened in this case.

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As part of her series on autism quackery, Chicago Tribune writer Trine Tsouderos has written another eye-opening article – this one about the drug OSR#1 that is being given as a “supplement” to children with autism.

The story highlights what I have been writing for years – that the current supplement regulation in the US under the Dietary Supplement Health and Education Act (DSHEA) is an anti-consumer farse.

OSR#1 is a drug. It is a compound that was manufactured by a company for its pharmacological activity. They claim it was developed as an anti-oxidant, but the Tribune reports that the compound may have originally been developed as an industrial chelator – a compound that binds heavy metals to clean them from soil or industrial spills.

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In a recent supplement of the journal Pediatrics is published the report of a consensus panel on the issue of gastrointestinal (GI) disorder in children with autism. This is not a new study and no new evidence is presented – it is a systematic review of the literature by 28 experts from various disciplines. These formal expert reviews are often a helpful way to make sense of a large and complex medical literature on a specific question.

The most significant finding of the panel is that:

The existence of a gastrointestinal disturbance specific to persons with ASDs (eg, “autistic enterocolitis”) has not been established.

In addition they found that there is no evidence for benefit from special diets. About 1 in 5 children with autism are on a special diet designed to improve the symptoms and outcome of autism, usually by removing gluten or casein from the diet, but there is simply no scientific evidence that such diets are helpful.

The alleged link between GI disorder and ASD was started by the now-discredited study by Andrew Wakefield in 1998. He proposed a “leaky gut syndrome” that allowed the measles vaccine to cause an infection which eventually led to the brain damage that causes autism. His research was later refuted and he is now even suspected of fraud. But the idea that GI disorders contribute to ASD was out in the public and took on a life of its own, separate from scientific evidence.

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The Centers for Disease Control (CDC) has published the results of their latest study on the prevalence of autism. There is no question that in the last 20 years the number of autism spectrum disorder (ASD) diagnoses has increased. What is also clear is that during this time there has been increased surveillance and a broadening of the diagnosis of ASD. Whether or not this accounts for the entire increase in ASD numbers, or if there is a true increase in there as well, is unknown.

Into that context, the CDC adds their most recent numbers, concluding:

In 2006, on average, approximately 1% or one child in every 110 in the 11 ADDM sites was classified as having an ASD (approximate range: 1:80–1:240 children [males: 1:70; females: 1:315]). The average prevalence of ASDs identified among children aged 8 years increased 57% in 10 sites from the 2002 to the 2006 ADDM surveillance year. Although improved ascertainment accounts for some of the prevalence increases documented in the ADDM sites, a true increase in the risk for children to develop ASD symptoms cannot be ruled out. On average, although delays in identification persisted, ASDs were being diagnosed by community professionals at earlier ages in 2006 than in 2002.

That 1 in every 110 children on average now carry an ASD diagnosis is not new news. This CDC data was actually released ahead of publication in October. At the same time a phone survey published in Pediatrics found 110 in 10,000 children carried an ASD diagnosis – or a little more than 1%. This 1% figure seems to be highly replicated – a National Health Services survey released in September also found a prevalence of 1% for ASD in the UK.

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Like my science-blogging colleagues, I get e-mail. I always appreciate it when readers (or listeners, in the case of the SGU) take the time to write. Sometimes the e-mails are questions from someone who disagrees with my position on a hot issue. I especially like these e-mails – they are good blog fodder, and I think the format of answering questions is more compelling and interesting than making a didactic argument.

Below is an example of the kind of question I most like to get – from someone who disagrees with me, but still manages to ask polite and cogent questions. This stands in stark contract to most hostile e-mail I get, which are just strings of ad hominems, straw men, and other logical fallacies. I get the impression (and some of my e-mailers have later even admitted this) that the e-mails were not meant as an opening to serious discussion, but as a venting rant into the ether of the internet.

Harold asks some very important questions about the alleged autism-vaccine link and research priorities, and I am happy for the opportunity to clarify my position. His e-mail begins below the fold:
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I and other science bloggers spend a lot of time and virtual ink doing damage control on bad science reporting in the media. It’s hard not to get a little jaded after wading through one terrible science article after another.  I discuss this problem and one stunning example of promoting pseudoscience passing for journalism today on SkepticBlog.

But occasionally I do make a point of celebrating good science journalism when I see it – and not just a solid piece discussing a new science news item, but a reporter tackling a controversial topic and getting it right. Most of the time mainstream journalism of fake scientific controversies or fringe ideas falls for the “false balance” fallacy – presenting fake science and real science side by side, as if they were equivalent, or just a matter of opinion. Or, even worse, we get token skepticism, or no skepticism at all.

Last week the Chicago Tribune printed a long piece on biological treatments for autism by Trine Tsouderos and Patricia Callahan, and an excellent piece it was. They clearly understand what the real story is – a subculture of fringe doctors and others who are essentially doing unethical experiments and children with autism. They are exploiting desperate parents (who then sometimes contribute to the exploitation of the next desperate parents) who are seeking any possible help for their children.

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Politics is partly about setting priorities and agendas, and therefore it is impossible to keep politics out of science. Politicians are also in control of the public’s purse strings, and so funding science also cannot be free from politics.

But ideally we should have an atmosphere in which politicians and funding agencies set broad agendas, and then let scientists decide the details of which research should be funded based upon the science. It is, in fact, an important trust that public money that is spent on scientific research be utilized optimally, and not to promote someone’s narrow ideological agenda. Examples of abuses are legion; my favorite example is the National Center for Complementary and Alternative Medicine (NCCAM), Senator Tom Harkin’s pet project in which the usual standards of medical research have been subverted to promote sectarian medicine.

We want scientists to follow their noses – to research those questions they think are most fruitful. But scientists are often forced to follow the funding, and this distorts the direction of research. Industry funding distorts research in ways that are advantageous to industry – a real problem that is being examined and there are at least attempts to deal with it. Government funding should be neutral, and provide a counterbalance to industry funding, but is often subverted to ideology. Even well-meaning patient-groups can distort funding if they try to dictate what scientists should be researching in exchange for their fund-raising, with detrimental effects.

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A new study published online in Environmental Health Perspectives shows no correlation between blood mercury levels in 2-5 year old children and autism or developmental delay. This study adds to the growing evidence that environmental exposure to mercury, from any source, is not a risk factor for autism.

The study looked at 452 children aged 2-5 (which is a robust sample) with either autism spectrum disorder (ASD), other developmental delay (DD), or typically developed (TD). They found that children with ASD and DD had lower levels of blood mercury than TD controls. They further found that ASD and DD children tended to eat less fish, and as fish is by far the most significant source of mercury exposure, this explains their lower levels.

The researchers then adjusted for reported exposure to fish as well as other known sources of mercury and found that the adjusted level of mercury were the same for all groups. The levels were also similar to established national norms, meaning that the population being studied and the methods used are likely representative.

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