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Epidemic or greater awareness?

4 Oct

OK, this one has been beaten to death. I am amazed that it still think that there is evidence of an “epidemic”. This is especially true of those who rely on the California Department of Developmental Services (CDDS) data. These data are so muddy as to be able to hide a real increase or a real decline.

These data have severe limitations as noted before on this blog. They are not “epidemiological” data. They are not a census of those with autism in California. They are a count of who is getting services and this can and does vary dramatically over time and geography.

1984 Birth CohortThat said, let’s take a look at how service rates change with time for a given birth cohort. (click to enlarge). [edit: this is the 1984 cohort] This is much as you would expect. Kids start being listed at age 3. The number increases year after year until a plateau is reached. This happens at about age 7 or 8. There is some slope to the curve: additional kids are being added to the roll even after 8 years old.

This is very straitforward and expected. But, what happens over a longer time to this cohort? Click to enlarge this graph.1984 Birth Cohort CDDS Data Ignoring the obviously leading arrow and label for now, it is abundantly clear that something unexpected has happened. A second large increase in the number of clients is observed. Why would this happen? Well, one of the possible explanations is shown by the arrow. In 1997, the “epidemic” was declared. Autism awareness increased dramatically.  One possibility is that the 1984 cohort was still in school where people might notice them and identifiy them. This cohort nearly doubled in numbers from 1997 to 2003. 

This brings up so many questions, many of which we just can’t answer with the data we have access to.

It would be interesting to see if there was substitution. Were these kids (heck, teenagers) listed by CDDS under a different label?

How did roughly half the kids in this cohort avoid detection? I think the new phrase is “it’s like missing a forrest fire”. Well, these forrest fires were blazing for 13 years before people started noticing them.

Also, what happened to other cohorts? Well, for one thing, a similar jump in cohort size around 1997 is observed for birth years in the 1980’s and early 1990’s. It isn’t as clear or as consistent birthyear-to-birthyear as you go back in birthyears, but it is observable in some birth cohorts. One example where one can see this is the 1960 birth cohort, which increased about 15% around year 2000.

That last paragrah wasn’t clearly written, I admit. But if you are thinking, “what? The CDDS ‘found’ 15% more 40 year olds?” you read it right.CDDS clients by year as listed in 1986 and 2007 This graph (click to enlarge) shows the number of CDDS autism clients as listed in 1986 and 2007 by birth year. The 1986 (in black) data are the same as shown before. The drop in the client count in the early 1980’s is an artifact: those kids weren’t identified yet in 1986. The 2007 client count (in red) show something very interesting, at least to me.

There is an increase in autism clients for almost all the birth year groups. 40-year olds, 50 year-0lds, even older people were added to the client list as “autistic”. Again, we don’t know if or how these people were classified before the “epidemic”. They could have been (and likely were, in my opinion) clients listed in another category in 1986.

Let’s take a look at the difference between these two curves. I included data for people with birthdays in the early 1980’s, but these are not reliable. Those people weren’t through the first round of identification by 1986. 

CDDS Autism Clients in 1986 and 1997 by birth yearThe graph shows the difference as a percentage increase. This allows us to see the older cohorts easier. At the same time, it allows people to accuse me of doctoring the data to make it seem like a bigger effect than it really is. That would be an obvious way to try to divert attention from the fact that the “epidemic” caused a roughly 40% increase in CDDS autism clients born in the 1960’s. For those clients born from 1940-1955, the increase was 70+/-28%.

Think about that a second. Autism amongst forty year old people increased by 70% during “the epidemic” years.

How can this be? How could CDDS have missed people with autism for forty or fifty years? Sure, some of these people may have moved into the state. Some of them may have been cared for by family and not been served by CDDS. The trends of these birth cohorts with time do not show the sharp rise in the late 1990’s as observed above for 1980’s cohorts.  For me, this is suggestive that the those who could be identified in the school systems, were.

Obviously there are a lot of open questions here.  How and why these increases were observed is a big question.  Why no one has seen fit to mention this before is another question.  The CDDS did not create these data sets for me.  Someone else has been paying for that for some time, according to Mr. Kirby…who also hasn’t mentioned this.

People keep saying, “you can’t have a genetic epidemic”.  Well, you can’t have an epidemic of a childhood onset “disease” in forty-year-olds either.

____________________________________________

Edit: 

CDDS Clients vs. year for multiple birth cohorts First, note that the birth cohort in the first figue above is from 1984.  That is not clear.  Second, here is a graph with multiple cohorts.  Note that all the cohorts have an upswing in the client-numbers in the late 1990’s.  Even the 1990 cohort does this.  It does not appear to be based on age, but on calendar year.

What if you could prevent autism?

21 Sep

What if you could prevent autism?  What if there were a way that people could dramatically reduce the number of people born with autism? What if it took a concerted effort on the part of everyone to make it happen?  Should we do it?  Would people complain?

Would we respect the lessons of  the past if it had already happened?

Well, it may have already happened.  “May” as in it requires correlating one set of trends with California DDS numbers on Autism.  We all know how dangerous that can be.  CDDS data are not epidemological.  They don’t tell you how many people in California have autism, they tell you how many people in California are getting services under autism.  People who forgot the importance of that distinction have found themselves promoting an epidemic that didn’t happen. 

With that lesson in mind, let’s look at some CDDS data.  Let’s look at the number of clients with autism by birth year.  Further, let’s look at these data as they looked in 1986.  That is pre “epidemic”.  Pre DSM-IV.  That is before schools added autism as a separate category. 

  CDDS autism clients by birth year as recorded in 1986The data show something I didn’t expect: a drop in the number of autism clients.  Not just the noise that gets those promoting the epidemic to say, “look from one quarter to the next we see a drop”.  Nope, this looks like it could be the real deal, that elusive goal of those claiming an epidemic.  It happened in the 1970’s. 

Keep in mind that these data are from 1986.  So the drop in numbers in the 1980’s is because those people hadn’t been identified yet.  It isn’t “real”.

Also, keep in mind that these are raw numbers.  No attempt to normalize into a rate (individuals with autism per 1,000, say) has been made.  California went through a notable population increase over this time.  So, any drop in rate estimated (from these non-epidemological data) would be even greater.

Given this great amount of limitations, take a look at this graph.  These are the autism clients by birth year as reported in 1986.  The data are noisy, but I see a big plateau for kids born in the 1960s with about 100 clients per birth year followed by a second plateau in the 1970’s at about 75 clients per birth year.

That is an indication that there may have been  a roughly 25% drop from one decade to the next in the number of people with autism.   What happened?

Rubella prevalence in the USWell, since I recently posted about the dangers of only digging deep enough to support your own pet theory (and that is good advice), I’ll put this forward as a “Medical Hypothesis”.  Consider this: the Rubella vaccine was licensed in the U.S.  in 1969.  What happened before that?  There was a Rubella epidemic in the 60’s.  Lot’s of kids were born with CRS, Congentital Rubella Syndrome: a known cause of autism.

What if the Rubella vaccine is reducing the number of kids born with autism?  Wouldn’t that be a good thing that should catch the attention of the “autism community”?  It is a little strange that one would have to use this route. Keeping Rubella at bay results in a lot fewer deaths, including the unborn.  Also, fewer would become deaf, fewer would have congenital heart defects.

From the CDC:

The greatest danger from rubella is to unborn babies. If a woman gets rubella in the early months of her pregnancy, there is an 80% chance that her baby will be born deaf or blind, with a damaged heart or small brain, or mentally retarded. This is called Congenital Rubella Syndrome, or CRS. Miscarriages are also common among women who get rubella while they are pregnant.

I would have thought that would be enough to get the point across: Rubella is something to prevent.  Perhaps the vaccine is a good thing?  Perhaps it is working?  I don’t think there is any “perhaphs” about it.  Overall, preventing Rubella is a great thing.  But some people seem to want to deny that vaccines even work.

Take a very rough estimate.  Assume from these data that 25 people a year in California alone have had autism prevented by the Rubella vaccine.  From 1970 to 2007, that works out to 675 people.  And that is just a secondary benefit.

Maybe by calling the Rubella vaccine “preventing autism” it will catch the eye of those who have somehow forgotton how bad this disease is.

Why Aren’t You “Scared To Death”?

13 Sep

Do you miss Dan Olmsted’s writing? He now apparently showcases his version of scientific brilliance over at Rescue Host.

Recently, he tried to pass off the Flu shots and Chinese mercury hypothesis (which I thought was David Kirby’s, but I guess I was wrong) without much more than unfounded speculation and belief.

California, of course, is ground zero as we watch autism rates keep rising — even after mercury was “removed” from childhood vaccines starting in 1999 (the situation is much more complicated than that, since more and more pregnant women and younger and younger kids are getting mercury-preserved flu shots). So if you believe as I do that autism is fundamentally an environmental illness that whacks a subgroup of susceptible kids, mercury from China — or anyplace else — is every bit as important as mercury from vaccines.

I asked him the following in the comments:

If you wouldn’t mind Mr. Olmsted, take a look at a graph of the 3-5 year-old autism caseload cohort for the past 5 years.

Such a graph would include children born at the starting point of the “removal” in 1999 you mentioned. What do you see? Does the trend look linear to you?

Do you really believe there is combined flu shot uptake and airborne mercury data that would exactly and inversely match (in dose and effect, if any) the reduction the use of thimerosal in childhood vaccines in order to produce a trendline with an R-squared value of .9954 for this time period?

You can view such a graph here.

To which he replied:

An “R-squared value of .9954” is way beyond my non-scientific expertise. All I can say is that thimerosal use has actually been increasing in by far the most vulnerable group — pregnant women — and that at least some studies suggest that greater pollution directly correlates with a greater risk of autism. If the CDC had recalled all thimerosal-containing vaccines in 1999, we’d have a genuine “natural experiment.” But we don’t. Nor will the government study autism rates in never-vaccinated kids; the survey by Generation Rescue found ominous correlations between vaccines and NDs including autism, but it’s been widely ignored.

The survey by Generation Rescue? Right. Did he just make up that part about thimerosal use increasing in pregnant women? It kind of looked like it to me, so I asked and commented as follows:

What evidence do you have that thimerosal use actually increased in pregnant women for the period immediately following the “removal” of thimerosal from childhood vaccinations? (required to make your hypothesis work)

The majority of childhood vaccines were thimerosal-free or contain only trace amounts by 2002 (more on that below). Here’s flu shot uptake estimates for pregnant women for the three years that follow:

2002 – 12.4±3.9 %
2003 – 12.8±4.4 %
2004 – 12.9±5.0 %

Source

Note: there is an increase in the estimate for 2005, but children born in 2005 and later are not old enough to be reflected in the 3-5 year-old California autism caseload cohort yet. Additionally, estimates for 2006 were back down to 12.9 percent.

Source

Mark Blaxill and JB Handley showed up in the comments following that, and Olmsted apparently did not reply further. So the question of where Dan Olmsted might have found any data to make his Flu shots and Chinese mercury hypothesis plausible, will have to remain unanswered for now. But, while we’re on the subject of data-free gibberish, have a look at a piece of something posted by Dan Olmsted at Rescue Host on September 11th.

At some point, common sense has to prevail. For instance, let’s stipulate that better diagnosis accounts for a gargantuan 36 times more cases of bipolar disorder among kids over the past 10 years. That still would mean that the condition quadrupled in a decade — suspiciously, the same decade that autism, asthma, ADD, ADHD etc. soared out of sight. The deniers have to explain away every digit of that 40-fold number, because even a “mere” fourfold increase in the real incidence would be deeply disturbing. How can anyone be certain that one-tenth of that 40-fold increase isn’t actually real? And if they can’t be certain, why aren’t they scared to death?

Emphasis mine.

An appeal to “common sense” is a sure sign that what follows is probably not data that supports his hypothesis. Is common sense really the best way to arrive at correct answers about any subject for anyone, regardless of their background? What do statements like, “An ‘R-squared value of .9954’ is way beyond my non-scientific expertise”, tell us about the context to which Mr. Olmsted’s “common sense” might be reliably applied? Is autism epidemiology likely to be anywhere near Olmsted’s knowledge and expertise?

Sometimes common sense seems like a good way to operate, but the reality is that many things in science have quite complex answers. It’s also the case that science does not have all the answers (nor does it claim to). None of this will apparently stop Mr. Olmsted from forging ahead with assertion and anecdote in the rest of his post of course.

Did you catch this part of that paragraph above?

“…suspiciously, the same decade that autism, asthma, ADD, ADHD etc. soared out of sight.”

Did you see any real data or science whatsoever that actual autism prevalence “soared out of sight” in the past ten years? Me neither. So here you go any “Flu shot and Chinese mercury” proponents, now is your chance to post that real data or science in the comments – really, Mr. Olmsted needs your help if he’s to avoid the inevitable “You’ve got nothing!”. Either that, or get him a new hypothesis to work with (something with corroborative data preferred).

As for Mr. Olmsted’s final question in that paragraph, I’d like to answer it from one perspective.

We can’t be absolutely sure that there hasn’t been some real increase in autism prevalence, there might have been. To conclude that there has been a real increase in autism prevalence wouldn’t require much more than good data that shows it’s actually true. However, to conclude that there has been a real increase without supporting scientific evidence, but based on “stories”, is unscientific, if not a bit silly.

I can’t be absolutely 100% certain that an alien abduction has never occurred, but this lack of certainty does not translate to “therefore alien abductions are real”. I can’t be absolutely 100% certain that bigfoot doesn’t exist either, but again, that lack of certainty does not translate to “bigfoot is real”. I don’t live in fear of being abducted by aliens or encountering a hairy giant biped while on a hike with the kids, despite an abundance of “stories” about these things. I’m also not “scared to death” that there could indeed be an increase in the actual prevalence of autism. It is a possibility, but I have seen no evidence of it’s truth. I do see an increase in storytelling though.

CDDS and full syndrome arseholes

14 Jul

Every god-damn quarter, without fail. Every single one. The CDDS data gets released – Rick Rollens releases his usual ‘full syndrome’ crapola and tells us how autism is still skyrocketing and does his best Chicken Little impression and David Kirby chews at the edges of the data to try and find something that will support the idea that thiomersal plays any kind of role in autism.

Its getting really, really old.

Please let me say it to you one more time.

CDDS is not good source data for epidemiology. They say so themselves.

When CDDS refer to ‘full syndrome autism’ they are not, repeat, not referring to classical autism. See this form here? CDDS use it to record autism. It was designed in the 1970’s. The version in use today was last updated in 1986. Don’t believe me? Ask them.

Item 23 is where the term ‘full syndrome’ is used. This term is today utterly without meaning. It is the only place to record autism at all.

If we trun to this document and go to page 71 we can see the section dealing with autism. In terms of _having_ autism, a person either can, can’t or have autistic-like symptoms associated with mental retardation. Its not until page 77 that we get to any kind of recording of degree of severity. *Note that this has no bearing on whether a person _has_ autism* . That is already indicated.

Here is what CDDS passed on to me. I promised not to attribute this quote so I won’t but if anyone wants to double check then an email to CDDS would back me up:

The current CDER was written in 1978 and updated in 1986, which is why the language is so out of date ( e.g., Residual Autism). California has clinicians in the field who are, of course, using modern criteria in their assessments but then they have to go backwards and try to fit those kids into the 1986 CDER. So you are going to have Aspergers kids, PDD-NOS kids in both categories 1 and 2. Categories 1 and 2 are called “Autism.” But because there are so many clinicians, using lots of different techniques for evaluation, there is a lot of inconsistency and enrollment figures should not be misused as epidemiological data.

You might also be interested in a quote from Rita Eagle PhD of the California Dept. of Developmental Services (DDS) to Journal of Autism and Developmental Disorders, Vol. 34, No. 1, February 2004:

To many clinicians, it appears that more and more children who, in the past, would never have been referred to the regional centers–for example, bright but anxious and slightly socially inept kids with average or better IQs and children who, in the past, had been or would have been diagnosed as ADHD, OCD, ODD, anxiety disorder, learning disabilities, psychotic, and so forth—are now being diagnosed wit high-functioning autism and/or Asperger syndrome and referred to the regional centers for services.

I really don’t know how much clearer this information can possibly be. And yet we still have full syndrome arseholes like Rick Rollens sending out emails that contain:

As stated many times before in these Reports, the numbers being reported by DDS only reflect those children that have received a professional diagnosis of full syndrome DSM IV autism, and do not include those with any other autism spectrum disorder such as PDD, NOS, Asperger’s, HFA, Retts, etc

So Rick:

a) Its impossible for a document/process written in 1978 and updated in 1986 to reflect the DSM IV.
b) The numbers quite clearly _do_ contain PDD-NOS, Aspergers Syndrome and Rett Syndrome.

And hey, if CDDS data is good then how would the following be explained?

It’s now 2005. Mercury started to be removed from vaccines roughly in 2001, we don’t know exactly when as the FDA won’t tell us, but kids entering the system now, four year olds for example in California entering the Dept of Developmental Services [CDDS] were born in 2001. So those kids theoretically get less mercury on average than kids born in 2000. So we should see fewer cases entering the system this year than we did last year.

– David Kirby

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….total cases among 3-5 year olds, not changes in the rate of increase is the right measure.

– David Kirby

Late 2006 should be the first time that rates go down,” said Handley. “If they don’t, our. hypothesis will need to be reexamined.

– JB Handley

Problems with prevalence

8 Feb

The ‘autism epidemic’ lives and dies on prevalence. The assumed prevalence in the US again came under the spotlight due to a CDC study being released that showed an increased rate of prevalence.

Autism is more common in the United States than anyone had estimated, affecting about one in every 150 children, the U.S. Centers for Disease Control and Prevention reported Thursday.

Pfft – that’s nothing. Us Brits can post a recent prevalence estimate of one in every 100 children and as Joseph shows a 1% prevalence is not really anything new either. What _is_ new is that this new study from the CDC is slowly beginning to approach the prevalence rate of around 1% reported in the UK, Canada, Germany, Sweden and, less strongly, Norway.

So when I say ‘increase in prevalence’ – and when these people refer to the same – are we all saying that the prevalence rate is actively increasing? No. No one (at least no one legitimate) is suggesting that there is an active increase in the amount of people who _are_ autistic. Rather the suggestion is that we continue to move (some countries faster than others) to an international autism prevalence of (as yet) some undiscovered figure, but one which is definitely over 1% where rates will probably plateau with minor tweaks up and down.

An interesting quote from the same interview:

“The older statistics always estimated 70 to 75 percent of kids with autism had cognitive impairment,” Rice said. “We found 33 to 62 percent.”

So, ask yourself, is this a cognitive impairment ‘anti-epidemic’? If you believe the changes in autism prevalence represent an epidemic, surely it must follow that these figures represent an ‘anti-epidemic’?

Or maybe, just maybe, this is an illustration of two things a) the changes in diagnostic criteria for autism as a whole and b) improved diagnosticians and diagnosing techniques.

As a further exercise and as I’ve been perseverating a tad on them of late, lets see what the changing face of prevalence can tell us about CDDS data as of 2005 (year end).

OK, as of 2005, the population of California was 36,132,147. The number of CDDS registrants as of 2005 was 29,424. This gives an autistic population in CA in 2005 of 0.08% according to CDDS.

We now have three potential prevalence rates to measure the accuracy of CDDS – do the CDDS numbers accurately match any of the three prevalence rates? Well, clearly the answer is no. At a rate of 1 in 166 (the ‘old’ prevalence rate) there should be an autistic population of 0.60% and using the ‘new’ 1 in 150 rate there should be an autistic population of 0.66% – and we already know that in Canada and parts of Europe the rate is 1%.

Let’s be clear here, CDDS is reporting between 8.1% and 13.5% (depending on the prevalence rate you go with) of all autism in California. That’s not so good. Especially when even _those_ figures have stopped supporting your hypothesis.