Articles

Posts Tagged Autism

The final nail in the mercury-autism hypothesis?

PROLOGUE: BAD LUCK AND BAD TIMING

Two and a half years ago, very early in the history of this blog, I wrote one of my usual logorrheic (although I prefer the word “comprehensive”) posts entitled Mercury in vaccines as a cause of autism and autism spectrum disorders (ASDs): A failed hypothesis. In that post, I characterized the scientifically discredited notion that the mercury in the thimerosal preservative that used to be in several childhood vaccines was the cause of the “autism epidemic” as “one of the most pernicious medical myths of recent years.” And so it is. I like to characterize the notion that thimerosal-containing vaccines (TCVs) cause autism as the American version of the British myth, popularized by Andrew Wakefield and a sensationalistic British press, that the measles-mumps-rubella (MMR) vaccine causes autism and “autistic enterocolitis.”

Both notions were based on confusing correlation with causation, aided and abetted by some truly bad science, and both notions have been painfully difficult to dislodge. Indeed, in the case of Wakefield, only now that Wakefield was stripped of his license to practice in the U.K. by its General Medical Council, leading to The Lancet finally doing what it should have done six years ago and retracting Wakefield’s 1998 study that sparked the MMR frenzy in the U.K. and arguably kickstarted the modern anti-vaccine movement, do I sense that journalists are finally “getting” that science does not support the idea that the MMR vaccine causes autism. Andrew Wakefield may be trying to fight back with his book Callous Disregard after his disgrace was complete, basking in the glow of admiration of die-hard anti-vaccine groups, but, for now, at least, Wakefield and his MMR fear mongering are yesterday’s news, and that’s a very good thing indeed–at least for as long as it lasts.

Perhaps it is the fall of Andy Wakefield that has led to an apparent resurgence of the concept that mercury in TCVs somehow causes autism, after having faded into the background after the CDC and AAP recommended that thimerosal be removed from all childhood vaccines in 1999 and the last TCV having expired towards the end of 2001. After all, if the hypothesis that TCVs cause autism had been correct, we should have expected to see a marked decrease in the incidence of autism and autism spectrum disorders (ASDs) within about 5 years of 2002, given that the vast majority of cases of ASDs are diagnosed between the ages of 2 and 5. We have not, and, even though its adherents have kept moving the goalposts back regarding the date that we should start to see a leveling off and drop in the incidence of ASDs, starting with 2005, then 2007, and now, apparently, 2011 (which is only less than four months away, by the way), even Jenny McCarthy’s anti-vaccine organization originally founded by J.B. Handley and his wife, namely Generation Rescue, began demphasizing mercury in 2007, after having stated flatly on its website that autism is a “misdiagnosis for mercury poisoning” for so long. Since then, “too many, too soon” has been the favored propaganda talking point.

Of course, not every crank is ready to abandon the myth that TCVs cause autism. Indeed, tomorrow two mercury militia “heavy hitters” and bloggers for the anti-vaccine propaganda blog Age of Autism, Mark Blaxill and Dan Olmsted, will be releasing a book entitled Age of Autism: Mercury, Medicine, and a Manmade Epidemic. In anticipation, four weeks ago I actually e-mailed the publicist to send me a review copy of Age of Autism. I have yet to receive the book. I wonder why. Be that as it may, it amuses me that the official release of the release of the not-so-dynamic duo of the mercury militia’s book actually will one day after a study that is arguably the last nail in the coffin of the very dead hypothesis that TCVs cause autism was released. Either the great pharma conspiracy is far more conniving and effective than even J.B. Handley thinks, or Blaxill and Olmsted’s luck is just that bad. As I anticipate the conspiracy mongering posts about this bad timing aside, let’s just take a look at this last coffin nail, which is a study by Price et al that was released today in the journal Pediatrics entitled Prenatal and Infant Exposure to Thimerosal From Vaccines and Immunoglobulins and Risk of Autism.
(more…)

Posted in: Neuroscience/Mental Health, Vaccines

Leave a Comment (56) →

Terrible Anti-Vaccine Study, Terrible Reporting

One of my goals in writing for this blog is to educate the general public about how to evaluate a scientific study, specifically medical studies. New studies are being reported in the press all the time, and the analysis provided by your average journalist leaves much to be desired. Generally, they fail to put the study into context, often get the bottom line incorrect, and then some headline writer puts a sensationalistic bow on top.

In addition to mediocre science journalism we also face dedicated ideological groups who go out of their way to spin, distort, and mutilate the scientific literature all in one direction. The anti-vaccine community is a shining example of this – they can dismiss any study whose conclusions they do not like, while promoting any horrible worthless study as long as it casts suspicion on vaccines.

Yesterday on Age of Autism (the propaganda blog for Generation Rescue) Mark Blaxill gave us another example of this, presenting a terrible pilot study as if we could draw any conclusions from it. The study is yet another publication apparently squeezed out of the same data set that Laura Hewitson has been milking for several years now - a study involving macaque infants and vaccinations. In this study Hewitson claims a significant difference in brain maturation between vaccinated and unvaccinated macaque infants, by MRI and PET analysis. Blaxill presents the study without noting any of its crippling limitations, and the commenters predictably gush.

(more…)

Posted in: Science and Medicine, Vaccines

Leave a Comment (25) →

The genetics of autism

Autism and autism spectrum disorders (ASDs) actually represent a rather large continuum of conditions that range from very severe neurodevelopmental delay and abnormalities to the relatively mild. In severe cases, the child is nonverbal and displays a fairly well-characterized set of behaviors, including repetitive behaviors such as “stimming” (for example, hand flapping, making sounds, head rolling, and body rocking.), restricted behavior and focus, ritualistic behavior, and compulsive behaviors. In more mild cases, less severe compulsion, restriction of behavior and focus, and ritualistic behaviors do not necessarily preclude functioning independently in society, but such children and adults may have significant difficulties with social interactions and communication. Because ASDs represent a wide spectrum of neurodevelopmental disorders whose symptoms typically first manifest themselves to parents between the ages of two and three, the idea that vaccines cause autism and ASDs has been startlingly difficult to dislodge and has fueled an anti-vaccine movement, both here in the U.S. and in other developed nations, particularly the U.K. and Australia. This movement has been stubbornly resistant to multiple scientific studies that have failed to find any link between vaccines in autism or the other favorite bogeyman of the anti-vaccine movement, the mercury-containing thimerosal preservative that used to be in many childhood vaccines in the U.S. until the end of 2001. Add to that the rising apparent prevalence of ASDs, and, confusing correlation with causation, the anti-vaccine movement concludes that vaccines must be the reason for the “autism epidemic.”

In reality, autism and ASDs appear to be increasing in prevalence due to diagnostic substition, better screening, and the broadening of the diagnostic criteria that occurred in 1994. Autism prevalence does not appear to be rising, at least not dramatically, at all, as the prevalence of ASDs, when assessed carefully, appears to be similar in adults as it is in children. If the true prevalence rate of autism and ASDs has increased, it has not increased by very much. In reality autism appears to have a major and probably predominant genetic component, and several scientific studies over the last few years have linked autism with various genetic abnormalities. Not surprisingly, given the varied presentation and severity of ASDs, these studies have not managed to identify single genes that produce autism or ASDs with a high degree of penetrance (probability of causing the phenotype if the gene is present). Indeed, one can argue that the state of current evidence is that ASDs are due to multiple genes, perhaps dozens or hundreds. Again, this is not surprising given the heterogeneity of ASD severity, presentation, and symptoms.

One of the more surprising studies supporting a genetic basis for autism appeared to much fanfare in Nature last week. The study by Pinto et al, looks at the functional impact of global rare copy number variation in autism spectrum disorders. Its results are rather surprising in that the large team of investigators (studies of this type take a lot of people to carry out) found that it may be relatively uncommon copy number variations in various genes that lead to the phenotype of autism or ASDs.
(more…)

Posted in: Neuroscience/Mental Health, Science and Medicine, Vaccines

Leave a Comment (49) →

Nine differences between “us and them,” nine straw men burning

I’ll start this post by admitting right up front: I blatantly stole the idea for the title of this post from Mark Crislip’s most excellently infamous post Nine questions, nine answers. Why? Because I really liked that post and felt like it. Also, there seems to be something about the number nine among anti-vaccine zealots: Nine “questions.” Nine circles of hell.

Nine straw men.

I’m referring to an amazing post that appeared on the anti-vaccine crank blog Age of Autism over the weekend by contributing editor Julie Obradovic entitled The Difference Between You and Me. In this post, Julie describes not one difference, but nine differences, that she perceives between herself (and, apparently, by generalization other parents who have become believers in the myth that vaccines cause autism) and people like SBM contributors and (I hope) the vast majority of our readers, who support science-based medicine, understanding that correlation does not necessarily equal causation and that, most importantly, science not only does not support the belief that vaccines cause autism but provides us with copious evidence that there almost certainly no link between the two. Actually, there are more than nine differences, as Ms. Obradovic packs multiple apparently related differences around each of her nine “differences” and then complains that Alison Singer and, apparently by generalization the rest of us who support SBM and oppose the anti-vaccine movement, misrepresent the reasons why she and her merry band of anti-vaccine activists reject the science that has failed spectacularly to validate their deeply held belief that vaccines cause autism and all sorts of other health consequences. Her post ends up being a collection of straw men constructed to Burning Man size, each of which she then applies a flamethrower of burning nonsense to with self-righteous gusto.
(more…)

Posted in: Public Health, Science and the Media, Vaccines

Leave a Comment (79) →

Andrew Wakefield Fights Back

Dr. Andrew Wakefield was almost single-handedly responsible for frightening the public about a possible association between autism and the MMR vaccine. His alarmist recommendations directly led to lower vaccination rates and a resurgence of measles to endemic levels in the UK. The MMR/autism interpretation of his 1998 article in The Lancet was retracted by 10 of his 12 co-authors. The article itself was “fully retracted from the public record” by The Lancet. And now Wakefield has lost his license to practice medicine after the General Medical Council’s exhaustive 2½-year review of his ethical conduct.

His career was in shreds and there was only one way left for him to fight back: to write a book. Callous Disregard: Autism and Vaccines — The Truth Behind a Tragedy has just been published. I tried hard to read it with an open mind and to understand his point of view. He did make some points that I will accept as valid unless they can be refuted by the others involved. Some of what he said and did was apparently misinterpreted and distorted by his critics. But the book did not convince me that he was an ethical, rigorous scientist or that MMR is linked to autism or to bowel disease. In my opinion the book does nothing to scientifically validate his beliefs or to excuse his behavior, but rather boils down to self-serving apologetics and misleading rhetoric. It also undermines his claim that he is a good scientist by showing that he values anecdotal evidence (“listening to the parents”) over experimental evidence. (more…)

Posted in: Book & movie reviews, Vaccines

Leave a Comment (48) →

Bogus Diagnostic Tests

A few years ago a friend asked me to comment on advice given to her adult daughter by a psychiatrist whom she’d consulted for depression. The psychiatrist had recommended testing samples of saliva and urine for hormone and neurotransmitter levels, the results of which would likely indicate a need for supplements to correct deficiencies or imbalances. According to the psychiatrist, who had an academic appointment at a medical school in New York City, “I have been using these supplements with a great deal of success.” My friend is not medically or scientifically sophisticated, but this made her a little uncomfortable. In that, she was entirely justified.

During our recent panel discussion at the NECSS, a member of the audience identified himself as a clinical pathologist at a major medical center, and wondered what he might do to become involved in the good fight against encroaching pseudoscience in medical schools. Clinical pathology is the medical specialty that concerns itself, in summary, with laboratory tests—their development, their validity, their interpretation, their usefulness and, by implication, their misuse. A topic that we haven’t much featured on SBM (we touched upon it here, here and here, and probably elsewhere) is that of bogus laboratory or other diagnostic tests.

Early in my own education in modern quackery, I found it particularly distasteful not merely that quacks misuse laboratory tests, but that several commercial laboratories market misleading tests. To the untrained eye these laboratories appear to be legitimate, even to the point of their being approved by apparently legitimate certifying bodies. We’ll discuss that below, but first let’s look more closely at the psychiatrist’s recommendations to my friend’s daughter and at other examples of bogus tests.

(more…)

Posted in: Health Fraud, Medical Ethics, Neuroscience/Mental Health, Politics and Regulation, Science and Medicine

Leave a Comment (29) →

Social Factors in Autism Diagnosis

There is no question that the incidence and prevalence of autism are on the rise. Starting in the early 1990s and continuing to today, there has been a steady rise in the number of children diagnosed with autism. Prior to 1990 the estimates of autism prevalence were about 3 per 10,000. The most recent estimates from the CDC and elsewhere now have the number at about 100 per 10,000, or 1%.

The burning question is – why are the rates increasing steadily? There are those, particularly in the anti-vaccine community, who conclude that the increase in prevalence is a real biological effect – an epidemic – and is evidence for an environmental cause (which they believe is vaccines, even though the scientific evidence does not support this position). However, the evidence strongly suggests that the rising prevalence of autism is largely an artifact of broadening the diagnosis and increased surveillance.

It should be noted that the data cannot rule out a small true increase in autism prevalence. Some hypothesize that increasing maternal and paternal age are contributing to the incidence of autism, but I will leave that question for another post.

A new study now adds significant support to the surveillance hypothesis – Ka‐Yuet Liu, Marissa King, and Peter S. Bearman from Columbia University, publishing in the American Journal of Sociology, report that the risk of being diagnosed with an autism spectrum disorder (ASD) correlates with social proximity to another family with a child with an ASD diagnosis. For those interested in this topic, the full paper is worth a read. While it gets technical at times, the authors do an excellent job of reviewing this topic in detail.

(more…)

Posted in: Neuroscience/Mental Health, Vaccines

Leave a Comment (57) →

Steven Higgs: Another antivaccine reporter like Dan Olmsted in the making?

April is National Autism Awareness Month, and as of today April is nearly half over. Do you notice anything different compared to the last couple of years? I do. Can you guess what it is?

The anti-vaccine movement’s usual suspects haven’t been all over the mainstream media, as they usually are this time every year, often as early as April 1 or even March 31. In fact, over the last couple of years I had come to dread April 1, not because it’s April Fools’ Day (although the things that made me dread that particular day were often indistinguishable from an April Fools’ Day prank, so full of idiocy were they), but rather the expected carpet bombing of the media by the likes of Jenny McCarthy, J. B. Handley, and their ilk, some or all of whom would show up on various talk shows to spread their propaganda that vaccines cause autism. For instance, last year Jenny McCarthy and her former boyfriend Jim Carrey showed up on Larry King Live! with Dr. Jerry Kartzinel (her co-author on her latest book of autism quackery) and J. B. Handley, the last of whom even contributed a guest post on Larry King’s blog, in which he touted an incredibly bad, pseudoscientific “study” commissioned by Generation Rescue. The “study” (and calling it a “study” is way too generous) was no more than cherry-picked random bits of data twisted together into a pretzel of nonsense, as I described. Around the same time, Jenny McCarthy was interviewed by TIME Magazine, an interview in which she uttered these infamous words:

I do believe sadly it’s going to take some diseases coming back to realize that we need to change and develop vaccines that are safe. If the vaccine companies are not listening to us, it’s their fucking fault that the diseases are coming back. They’re making a product that’s shit. If you give us a safe vaccine, we’ll use it. It shouldn’t be polio versus autism.

Soon after, Generation Rescue created a website called Fourteen Studies, which they promoted hither, thither, and yon. The idea of the website was to attack the main studies that failed to find a link between vaccines and autism and to promote the pseudoscientific studies that anti-vaccinationists like. In 2008, it was pretty much the same — well, worse, even. When she appeared on Larry King Live! with our old “friend,” anti-vaccine pediatrician to the stars, Dr. Jay Gordon, McCarthy shouted down real experts by yelling, “Bullshit!” (behavior trumpeted by Rachel Sklar of the Huffington Post).

This year? Oddly enough (and to me unexpectedly), there’s been almost nothing. J.B. Handley seems to be the man who wasn’t there. Well, not quite. It turns out that J. B. Handley has managed to get a little bit of fawning media attention, but just a little bit, in the form of an interview in The Bloomington Alternative entitled J. B. Handley: It’s unequivocal; vaccines hurt some kids. Apparently Mr. Handley has come down quite a bit in the world. Where’s his appearance with Jenny on Larry King Live! this year? Maybe it’s coming in the second half of the month. Or maybe the mainstream media, in the wake of the fall of Andrew Wakefield, have finally figured out how disreputable Generation Rescue is when it comes to vaccines. In the meantime Steven Higgs will have to do as a new mouthpiece for the anti-vaccine movement.

(more…)

Posted in: Neuroscience/Mental Health, Science and the Media, Vaccines

Leave a Comment (42) →

Autism Onset and the Vaccine Schedule – Revisited

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.

(more…)

Posted in: Science and Medicine, Vaccines

Leave a Comment (57) →

Yet another nail in the coffin of the myth that the MMR vaccine causes autism

Arguably, the genesis of the most recent iteration of the anti-vaccine movement dates back to 1998, when a remarkably incompetent researcher named Andrew Wakefield published a trial lawyer-funded “study” in the Lancet that purported to find a link between “autistic enterocolitis” and measles vaccination with the measles-mumps-rubella (MMR) trivalent vaccine. In the wake of that publication was born a scare over the MMR that persists to this day, 11 years later. Although peer reviewers forced the actual contents of the paper to be more circumspect, in the press Wakefield promoted the idea that the MMR vaccine either predisposes, causes, or triggers autistic regressions. Even though over the next several years, investigations by investigative journalist Brian Deer revealed that not only was Wakefield’s research funded by trial lawyers looking to sue vaccine manufacturers for “vaccine injury” when he did his research (for which he is now being charged by the U.K.’s General Medical Council with scientific misconduct), but during the Autism Omnibus trial testimony by a world-renowed expert in PCR technology showed that he was incompetent. Even worse for Wakefield, in February 2009 Brian Deer published a news expose based on strong evidence that Wakefield may very well have falsified data for his Lancet paper.

None of this mattered. Andrew Wakefield still enjoys a cult of personality among the anti-vaccine crowd that no revelation seems able to dislodge, even the revelation that at the time he was both in the pay of trial lawyers and working on his study, Andrew Wakefield was also applying for a patent for a rival measles vaccine. Indeed, the anti-vaccine propaganda blog Age of Autism bestowed upon him last year its “Galileo Award” as the “persecuted” scientist supposedly fighting for truth, justice, and anti-vaccinationism against the pharma-funded or brainwashed minions of the “Church of the Immaculate Vaccination.” In the meantime, MMR uptake rates in the U.K. have plummeted over the last decade, far below the level needed for herd immunity, to the point where, last year the Health Protection Agency declared measles to be once again endemic in the U.K., 14 years after the local transmission of measles had been halted.

Since Wakefield’s study was released, a number of studies have shown that there is no epidemiologically detectable link between vaccination with MMR and autism, including one by a researcher who once appeared to be a believer in the idea that vaccines are somehow linked with autism, Mady Hornig. Hornig actually tried very hard to replicate Wakefield’s 1998 Lancet study, only this time with more children, and she found no link between MMR and autism using methodology similar to Wakefield’s. None of these studies has had any effect on the anti-vaccine movement, except to motivate them to circle the wagons even more, as J.B. Handley of Generation Rescue did when he launched a website called Fourteen Studies, whose purposes are to launch fallacious and pseudoscientific attacks on studies failing to find a link between vaccines and autism (often involving accusations of being a “pharma shill”), to promote the lousy science that gives the appearance of supporting the hypothesis that there is a link between the MMR vaccine and autism, and then slime anyone who points out how deceptive their attacks were.

Now, yet another study has been released studying whether there is a link between MMR vaccination and autism. Yet another study has failed to find a link between MMR vaccination and autism. Yet another study is all set to be attacked by Generation Rescue and the anti-vaccine movement. The sad and sordid history of reactions of the anti-vaccine movement to studies that do not support its belief in the unsinkable rubber duck of a myth that vaccines cause autism. This study was published online in The Pediatric Infectious Disease Journal by a group from Department of Epidemiology and Preventive Medicine, Jagiellonian University, Collegium Medicum, Krakow, Poland (a Polish group, my people!) and entitled Lack of Association Between Measles-Mumps-Rubella Vaccination and Autism in Children: A Case-Control Study. It’s yet another nail in the coffin of the myth that the MMR causes or contributes to autism. Indeed, this study not only shows that MMR vaccination is not associated with autism but that it may even be protective against autism. True, for reasons I will discuss shortly, I doubt that that latter interpretation is true, but there’s no doubt that this study is powerful evidence against the view that there is an association between MMR and autism. Unfortunately, I fear that all the nails in my local Home Depot would not be enough to keep the zombie of this pseudoscience from rising from its grave yet again.
(more…)

Posted in: Clinical Trials, Vaccines

Leave a Comment (33) →
Page 3 of 6 12345...»