Friday, August 17, 2012

Is There Really an Autism Epidemic?

Spend a few minutes researching the subject of autism, and you will most likely come across someone who
will remind you that the rates of autism in the 1930s and 40s was somewhere around one in 10,000 (when the term "autism" was originally coined).  Then in the 1980s and 90s as visibility started to increase and when people started talking about autism, we were told the rates were one in several thousand children.  According to more recent CDC data, today the number is commonly quoted as one out of every 88 children has autism or an autism spectrum disorder (ASD).

Some may argue about the numbers saying they are slightly lower or slightly higher, but clearly the rate of autism is increasing and it isn't a gradual increase.  So what are the major reasons for this?  Antivaxxers are quick to point their fingers at vaccines as they claim the rise in the number of vaccines correlates with the rise in autism.  The correlation is true, but you could make the same argument surrounding increased use of cellphones, the spread of satellite television, the rising sales of bottled water, the usage of sonograms during pregnancy, or even the increasing popularity of Will Smith.  Does this mean we are going to blame the rising rate of autism upon the Fresh Prince?  Does this mean we should ban the sale of bottled water or mandate that the FDA perform studies proving it doesn't cause autism?  Of course not - because correlation does not equal causation, and correlation is not proof.

What we do know is that to date there have been no reputable peer-reviewed scientific studies that are able to prove a link between vaccines and autism in children, so even though antivaxxers are quick to point fingers, when pressed for evidence they come up short time and time again.  It isn't that nobody has tried to prove such a link, and many studies have been performed, but the reality is nobody has been able to tie vaccine usage to a rise in autism.  The science just isn't there.

So if we don't have any science proving vaccines cause autism, and if we don't yet have the science to prove autism is caused by any other environmental factor (including Will Smith)... what exactly is responsible for the alarming growth of autism diagnoses?

The simple answer is that we really don't know.  Scientists, doctors, and researchers are spending a great deal of energy trying to better understand autism, but the fact is to date there just hasn't been any definitive evidence to suggest any one particular "thing" is to blame.  Studies have focused upon vaccines and vaccine ingredients, but they have come up empty.  They have examined genetics and although some progress has been made, it is far too early to point fingers on any one root cause, or even several different causes.  Even things such as birth order, geography, age of the mother, and even the amount of rainfall in a region have been examined with some minor trends being noticed, but nothing which shouts "THIS is the cause of autism!".

However most experts in the field seem to continually remind us that the rising rate of autism really isn't as bad as it may seem.  The truth is, most of these experts chalk up the bulk of the increase to nothing more than increased awareness of the disease, and as such a greater understanding and familiarity results in more diagnoses.  We have actually discussed the awareness issue in the past, and if you couple the increased awareness with changing criteria for diagnosis over the years, you can start to see why it isn't so shocking that the number of children diagnosed with autism has grown so quickly.

The reality is, until 1980 the American Psychiatric Association (APA) didn't even have criteria for diagnosing autism, and it wasn't considered a separate diagnosis within the Diagnostic and Statistical Manual of Mental Disorders (DSM).  Then in 1980 with the publication of DSM III, Infantile Autism was first mentioned... but the criteria for diagnosis required the onset to occur prior to 30 months of age.  Ask many parents of autistic children and you will soon find that in many cases the child didn't start exhibiting autistic symptoms until they were three, four, or five years old.  So if it couldn't be called "autism", what diagnosis was attached to these children prior to 1980?

In 1987, DSM III-R was released which was a revision to DSM III.  In the updated text, Autistic Disorder was finally classified alone, and it included criteria for diagnosing the condition after 36 months of age.  Then in 1994, DSM IV was released which changed the criteria yet again and which created even more visibility of the condition.

So if the criteria for diagnosing autism wasn't even fully defined until the 1980s, and if the criteria have evolved several times since... do we really think it is feasible that the veritable 'explosion' of autism diagnosis is entirely legitimate, or could it be nothing more than simply a greater understanding of the disease, increased visibility, and a shifting of diagnoses from other mental disorders?

Regarding the last point, there have been several studies published which are trying to determine if that is the case.  Mark Roth of the Pittsburgh Post-Gazette wrote a piece a few years ago entitled Studies raise questions about increase in autism cases, and in his article he cites two separate studies which could contribute to the autism epidemic:
A 2006 study in the journal Pediatrics found, for instance, that the national increase in identified autism cases in elementary schoolchildren between 1984 and 2003 had been paralleled by a similar decrease in the number of children labeled as retarded or learning disabled.  
Paul Shattuck of Washington University in St. Louis, the lead author of the study, wrote last year that "in 44 of 50 states, the increase in autism was completely offset by a decrease in the prevalence of children considered 'cognitively disabled' or 'learning disabled.' "
[...] In a 2004 study, Lisa Croen of the Kaiser Foundation Research Institute in California and her team found that the increase in children diagnosed with autism in that state between 1987 and 1994 was almost exactly paralleled by a decrease in those diagnosed with retardation.
In case you actually care to read the complete studies, they can be found here:

Paul T. Shattuck, PhD - The Contribution of Diagnostic Substitution to the Growing Administrative Prevalence of Autism in US Special Education

Lisa A. Croen et al -  The changing prevalence of autism in California

I'm certain we all wish we knew the reason why autism seems so prevalent in today's society, but I'm as equally certain it isn't fair to blame the rise on environmental factors, vaccines, or yes even Will Smith.  I know it is easy to point fingers, but the science simply doesn't support such conclusions and it is dishonest to attempt to create a link when the evidence and legitimate science doesn't support it.  I understand the subject of confirmation bias, but when it comes to placing blame for a disease such actions can be incredibly dangerous.

So is the increase in autism really due to greater awareness and a expanded criteria for diagnosis?  Well, as much as I would love to give a 'yes' or 'no' answer, the truth is we simply don't know.  We do know that a large percentage of the increase can be attributed to awareness and a better understanding / better diagnosis of mental disorders, but I'm not about to go so far as to claim it is 100% responsible for the increase, because the data is inconclusive.

The problem lies when people make claims they can't support, and unfortunately there are a lot of self-proclaimed experts running around on the Internet spreading falsehoods and distorting the facts.  Most often those guilty of such distortions are associated with the anti-vaccination movement and they are quick to present their opinions as fact as they attempt to blame vaccines and pharmaceutical companies for 100% of the increase in autism even though the antivaxxers have been unable to produce one single peer reviewed study to support this claim.

This isn't to suggest they need a mountain of evidence, but wouldn't you think if someone was so convinced they have an answer, and if they are so willing to cite various doctors and 'experts' that they claim have come to the same conclusion... wouldn't you think they could at the very least cite one specific study that has been performed anywhere on the globe and published in a reputable medical journal which is able to prove a link between vaccines and autism?  Perhaps "prove" is too strong of a term, but wouldn't you expect them to be able to produce such a study which would even go so far as to make a bold assertion or which results in a strong relationship between the two?

Oddly enough when pressed for this evidence, antivaxxers make claims that such research "wouldn't be allowed" or that big pharma and/or the CDC would prevent it from being published.  They might also claim that such studies have been produced and that Andrew Wakefield was a pioneer when it comes to this subject, yet they conveniently ignore how Wakefield was caught falsifying data, modifying test results, and engaging in unethical behavior which resulted in not only his 'study' being retracted, but in him losing his license to practice medicine.

So when you really boil it down, antivaxxers use nothing more than excuses to explain why they don't have any data.  They make wild claims about how drug companies and the CDC control information yet they don't explain how Wakefield's study lasted for over a decade in a legitimate and respected medical journal before his fraud was finally exposed.  Antivaxxers make claims about how others are prevented from speaking, yet they ignore several prominent antivaxxer doctors and 'experts' who make their living from the anti-vaccination seminar circuit.  They make claims about how they would never be allowed to publish a study that proves autism is caused by vaccines, yet they ignore that none of these supposed anti-vaccination experts have made claims that reputable journals have rejected their studies.  Thus either these antivaxxers aren't willing to perform legitimate studies, or they have attempted to perform them and the results weren't what they had hoped, thus they sweep the results under a rug.

The truth is, antivaxxers have come to depend upon random conspiracy theories mixed with excuses, and they all but ignore logic and common sense.  They would rather spend time convincing the public that vaccines cause autism by the way of conspiracies and accusations as opposed to putting their reputations on the line and submitting a real medical study with their names on it.

I'm not going to fault anyone for having an opinion or even a theory.  I also wouldn't fault someone for being ignorant, because when people acknowledge they are ignorant it drives them to learn.  They seek answers, and if they strive to find the answers they will come out wiser and with a greater understanding of the facts.  However when people choose to remain ignorant, or when they are intellectually dishonest on purpose, or when they attempt to present wild unsubstantiated theories as facts... then they lose any right to have a place at the table, and they only serve to harm society with their desire to confuse via misinformation.

So the next time you hear about an antivaxxer making claims about how the rise in autism is directly related to the rise in the number of vaccines given to our children, go ahead and remind them prior to Will "Fresh Prince" Smith coming into the rap scene in the 1980s nobody had even heard of autism, and by the time Smith started starting in movies, autism was much more common.  Now that Smith is considered one of Hollywood's most successful leading men and one of the largest box office draws of our era, autism rates are at all-time highs!

Coincidence?  Correlation?  In the mind of an antivaxxer, it just mind be enough to claim causation.

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