Archive | Science RSS feed for this section

Incidence of autism in Berkshire

30 Sep

A Reading Borough Council report has shown that the incidence of autism in a borough of Reading, Tilehurst has increased over a period of eight years (2000 – 2008) from 68 to 186, more than doubling.

Lets put these figures in context of a few things. Firstly, thiomersal. Thiomersal was removed from all UK vaccines in 2004. The average age of autism diagnosis is five and a half (PDF) in the UK. This would mean that if thiomersal caused autism, a significant drop off in autism incidence would have been reported to have been occurring during late 2009 early 2010. This was not reported. This could be because the report did not go beyond 2008 but again there’s no mention of that either and I can’t find the relevant document on the Reading Borough Council website

Secondly, the report seems quite clear to refer to diagnoses of ASD which includes PDD-NOS and Aspergers Syndrome. Kate Manton of Berkshire Autism Society says:

People are being diagnosed much earlier now than they were 10 years ago. Children at two and a half are being diagnosed, if the condition is fairly severe.

Thirty years ago [someone] who was disruptive in class but fairly bright would be called naughty.

All good points and ones which mitigate against the obvious simplistic claims that there is some sort of epidemic of autism. There may well be some sort of ‘epidemic’ of _recognition_ of autism in all its many forms but thats not the same thing at all.

I’m left wishing I could get hold of a copy of the same data that the BBC did so to that end I have requested that the BBC send me a copy of the report. Hopefully they’ll reply.

The Age of Autism before thimerosal

28 Sep

Dan Olmsted and Mark Blaxill have written a book, The Age of Autism. It expands on Mr. Olmsted’s UPI series of the same name and uses the same logic: build a narrative that links mercury to illnesses and claim this as proof that mercury is the cause.

One can download the first 46 pages of the book for free on iTunes, buy the book, wait for it to come to your library or used book story (don’t count on the used bookstore route. Last report I got was only about 600 books sold in the opening time for this book). Or, one could just not read it ever.

If you want just an idea of what the book is about you can read a short excerpt on the publisher’s website. It starts with this simple statement:

We believe that autism was newly discovered in the 1930s for the simple reason that it was new.

Why was it new? If I understand the logic, the idea is that a new mercury compound was invented and tested around that time: thimerosal. From a recent interview, here are Dan Olmsted’s words:

What we did really was try to trace the rise of autism and that led us to look at the first eleven families who had children diagnosed in the 1930’s .. in the famous paper. We were able to identify seven of those first eleven kids, who were only known by their first name and last initial. When we did, we found what we thought was significant exposure of the family to mercury, in particular a new kind of mercury that came on the market .. that was used in fungicides for agriculture and in vaccines. So, we think as that happened, the first cases appeared. Then it seemed reasonable to believe that when the vaccine schedule that included much more mercury exploded in the 1990’s and so did autism .. there’s probably a connection that has been missed here.

First eleven kids? First studied or first with autism? They seem to be asserting that these are, indeed, the first autistics ever.


Thimerosal was invented in 1927. What strikes me odd about the position of Mr. Blaxill and Mr. Olmsted is that ten years before the invention of thimerosal, someone was born who would later be diagnosed with autism and receive support from the California Department of Developmental Services (CDDS) under the label “autism”. I know this because the data are publicly available. The CDDS data have been used for years to promote the idea of a vaccine-induced autism epidemic. Of course Mr. Olmsted and Mr. Blaxill are aware of these datasets as their colleague David Kirby made use of them many times over the years in his promotion of autism as vaccine injury, starting with his book “Evidence of Harm, Mercury in Vaccines and the Autism Epidemic: A Medical Controversy.”

Here is a list of the birth year and the number of people for each birth year who were getting services from the CDDS (note that these data were from the 1990’s. Some or all of these autistics may have passed on):

Birth-year number of CDDS consumers under the autism label
1930 1
1929 2
1928 3
1924 1
1923 1
1922 3
1917 1

There were not a lot of autsitics born before 1930 and still alive receiving services in the 1990’s, this is true. But, the oldest person in that group was 78 at the time. That’s one year older than Donald T. is this year, for those following that story. .Be that as it may, there are a number of CDDS consumers who were born before thimerosal was invented. It would be unwise to assume that these are all the people born before 1930 who were diagnosed autistic. They are but an example.

From what I’ve read, Mr. Olmsted and Mr. Blaxill spent about five years looking for the origins of autism (the time since Mr. Olmsted’s original UPI series of articles). They traveled internationally and, from their description at least, appear to have left no stone unturned in their search.

I wonder, did they ever challenge their assumption that autism was new? Did they seek out autistics who predated thimerosal and/or those who weren’t research subjects of Dr. Kanner? Or did they merely rework and expand on Mr. Olmsted’s previous work on Kanner’s subjects?

In their statement attempting to distance themselves from anti-vaccine groups, Mr. Olmsted and Mr. Blaxill state:

We don’t want crops to wither, or houses to rot, or children to die of vaccine- preventable illnesses. We simply want to stop an autism epidemic whose origin we believe can be discerned from a careful examination of its environmental history.

“Careful” examination. I wonder.

Safeminds comments on the latest thimerosal-autism study

21 Sep

SafeMinds is an organization which has long promoted the idea that thimerosal caused an autism epidemic. They may be the single greatest force that got the idea into the public’s eye, and got research funding focused on looking at the question.

SafeMinds has shown themselves to be very resistant to the very research they called for. Studies which show a lack of association between thimerosal containing vaccines (TCV’s) and autism are always rejected by SafeMinds. They are not alone in this, groups such as Generation Rescue and the National Autism Association (NAA) have also refused to accept the science.

So it was with no surprise that I read that SafeMinds had issued a statement against the study. The statement starts by pointing out that the study was funded and performed by those with conflicts–the CDC, Abt (an organization which does contract research for groups including the CDC), and HMO’s “which receive substantial funding from vaccine manufacturers to conduct vaccine licensing research”.

If we can’t use the HMO’s to work on such project, that sort of takes away the VSD as a tool. It certainly takes away the opportunity to do anything more than passive surveillance of the VSD data. One of the strengths of the Price study was the effort to do more than just review the medical charts. They worked with the children, both cases and controls, to verify that the autism counts were accurate. I bring this up because groups like SafeMinds frequently request access to VSD data.

SafeMinds also discusses the study methodology:

The study sample did not allow an examination of an exposed versus an unexposed group, or even a high versus a low exposed group, but rather the study mostly examined the effect of timing of exposure on autism rates.

There is much wrong with the above statement. Let’s start with where they are close to correct. The study sample did not allow for a direct comparison (with good statistics) of exposed vs. unexposed. This is true. This is because there are few unexposed kids (unexposed=no thimerosal exposure in this study. Unexposed does not mean no vaccines). If you look at exhibit 9.1.4 from the technical reports by Abt associates (the detailed reports on the study), you will see about 20-30 “unexposed” children. I.e. children with no thimerosal exposure. Of those, about 3-4 (out of 1,000) had no HiB, HepB or DTP vaccine vaccine at all (MMR isn’t listed as it is not a source of thimerosal). This is in line with estimates by the CDC of how many children are unvaccinated (typically about 0.4%). (as an aside–this points out how difficult it would be to do a good study of vaccinated vs. unvaccinated children using the VSD. Seriously, with 99.6% of kids receiving at least one vaccine, you would need a huge number of kids to get the number of unvaccinated needed for good statistics).

Here is that exhibit, with the no-exposure kids circled. (click to enlarge)

It would appear to this reader that the issue of unexposed vs. exposed isn’t so much one of “study design” as the limitations of the VSD itself. There just aren’t that many autistic kids to make a good statistical comparison of unexposed vs. exposed populations.

And, it should be noted, an unexposed vs. exposed comparison wasn’t the purpose of this study. One big question posed by SafeMinds and later picked up by groups such as Generation Rescue was simple: did the increase in thimerosal exposure from vaccines in the 1990’s result in an “epidemic” of autism? This is the question this study addressed.

I am at a loss as to why SafeMinds wrote this: “….or even a high versus a low exposed group, but rather the study mostly examined the effect of timing of exposure on autism rates”. Contrary to SafeMinds’ assertion, there is a large variation on thimerosal exposure in the study subjects. One of the surprising facts from this study was the number of children receiving thimerosal-free vaccines. This, together with variations in the number of vaccines administered, led to a much larger distribution in thimerosal exposures than one would expect based on the vaccine schedule alone.

Thus, the study was not on “timing” at all. It was, as advertised, on variation of exposure of thimerosal. The question is (at least to me), does the range of exposure amount to significant number of kids having “low” levels of exposure by SafeMinds’ definition?

The answer, it turns out, is yes.

Safeminds has the following statement on their website:

[Autism] remained rare (1 in 10,000) until the rapid escalation of vaccines beginning in the late 1980’s (from 10 shots of 7 antigens in 1983 to 36 shots of 15 antigens). Vaccines are a likely candidate to explain some, if not most of the rise in autism cases and possibly other chronic childhood disorders linked to immune system malfunction.

In one of the seminal papers on the thimerosal was co-written by SafeMinds founder Lyn Redwood Autism: a novel form of mercury
poisoning. In it, the authors state:

The discovery and rise in prevalence of ASD mirrors the introduction and spread of TMS in vaccines. Autism was first described in 1943 among children born in the 1930s (123). Thimerosal was first introduced into vaccines in the 1930s (7). In studies conducted prior to 1970, autism prevalence was estimated, at 1 in 2000; in studies from 1970 to 1990 it averaged 1 in 1000 (124). This was a period of increased vaccination rates of the TMS containing DPT vaccines among children in the developed world. In the early 1990s, the prevalence of autism was found to be 1 in 500 (125), and in 2000 the CDC found 1 in 150 children affected in one community, which was consistent with reports from other areas in the country (126). In the late 1980s and early 1990s, two new TMS vaccines, the HIB and Hepatitis B, were added to the recommended schedule (7).

I know I am spending a lot of time on this point, but it is important. The idea that there is a dose-response relationship between thimerosal and the presumed risk of autism is fundamental to the arguments made by groups like SafeMinds.

A sister organization to SafeMinds, Generation Rescue, says the same thing. In their take, “This is the schedule from 1983. If it worked for kids then, why doesn’t it work for kids now?”. Generation Rescue leader and spokesperson Jenny McCarthy wrote in her book, Healing and Preventing Autism: A Complete Guide, “In 1983, we had 10 shots on the vaccine schedule and autism was one in 10,000. Today there are 36 given and autism is nearing one in 100”. I.e. if we go back to the 1983 vaccine schedule, autism rates should drop to 1 in 10,000.

The 1983 schedule, as graphically presented in expensive full page newspaper ads by Generation Rescue, included 4 DPT shots (yes, the old whole cell pertussis vaccine). Each of those shots included 25 micrograms of mercury.

It strikes this reader that the thimerosal exposure from 4 DPT shots, the amount in the 1983 schedule that supposedly only resulted in 1 in 10,000 kids having autism, should be a “low” exposure amount. If groups are going to point to 1983 as a safer schedule and point to the increases in thimerosal exposure in the 1990’s as the major sign of the “epidemic”, we should be able to take their word that the levels in 1983 were somehow safer.

Let’s look at that figure from the Price study again, shall we? I will highlight how many kids have “low exposure” (i.e. comparable to the 1983 vaccine schedule) to thimerosal. Again, click to enlarge if you wish.

By my eye, something approaching 50% of the kids in the study received the thimerosal exposure of the 1983 schedule. Certainly more than 25%. Those highlighted in red have the same thimerosal exposure as kids did in 1983, so they should have the same autism prevalence that SafeMinds and Generation Rescue claim for that time period: 1 in 10,000.

If that group has a prevalence of 1 in 10,000–or even anything significantly lower than the prevalence of those with higher thimerosal exposure– this study would have found it.

In other words, a thimerosal-induced epidemic of autism didn’t happen. Even using the logic that SafeMinds used to hypothesize it in the first place:that, somehow, the thimerosal exposures in 1983 resulted in a low autism prevalence.

Yes, this is far from rigorous. But, so is the logic that claims that increased thimerosal exposure led to an autism epidemic.

If we read further into the SafeMinds response, we see some of the confusion:

The study sample did not allow an examination of an exposed versus an unexposed group, or even a high versus a low exposed group, but rather the study mostly examined the effect of timing of exposure on autism rates. There were virtually no subjects who were unvaccinated and few who were truly less vaccinated; rather, the low exposed group was mostly just late relative to the higher exposed group, ie, those vaccinating on time.

SafeMinds seems to be assuming this is a study on the number of vaccines, not the amount of thimerosal. They also don’t appear to have read the study thoroughly enough to note that, yes, there is a large fraction who were “less vaccinated” and, more importantly to this study, a large fraction who had lower thimerosal exposures. As noted above, the low thimerosal exposures result from the fact that many of the children received thimerosal free vaccines.

It is unfortunate that SafeMinds (and other groups like them) can not adapt to science as it comes out. Science which clearly shows that many of their hypotheses were wrong.

The Respectful Insolence blog also discusses some of the failings of the SafeMinds response.

Hannah Poling and the Pediatrics thimerosal study: two “big” stories with little press response

18 Sep

Two stories which are “big” news in some segments of the online autism community are the settlement amount for Hannah Poling and the recent study showing no link between autism and thimerosal in vaccines. While these have caused a fair amount of discussion on blogs (like this one), they didn’t generate that much press coverage.

We broke the Hannah Poling award story here on LeftBrainRightBrain on September 3. The story was ignored, even by such pro autism-as-vaccine-injury blogs as the Age of Autism until September 9th, when Sharyl Attkisson (who has some connection to the people at the Age of Autism blog) wrote about it for CBS.

There are a couple of dozen entries in Google News on Hannah Poling. Few major outlets. One that did carry it is the Atlanta Journal Constitution, the home town newspaper for the Poling family. In Settlement reached in autism-vaccine case the AJC quoted Dr. John Shoffner:

Dr. John Shoffner, a neurologist and national expert who has conducted research on autism and its causes, said researchers have found no link between vaccines and autism. And he said he strongly favors vaccination.

“The preponderance of data shows that vaccines are important and safe for children to prevent preventable and sometimes life-threatening infectious diseases,” Shoffner said. “I certainly am in favor and support the CDC’s as well as the American Academy of Pediatrics’ recommendation of vaccination.”

Shoffner is a co-author of a journal article that describes Poling’s case without naming her.

Edited to add: I forgot to include this quote from the Atlanta Journal Constitution:

“It’s critical to remember that the government has never compensated, nor has it ever been ordered to compensate, any case based on a determination that autism was actually caused by vaccines,” said Martin Kramer, communications director for the Health Resources and Services Administration. The National Vaccine Injury Compensation Program is part of the administration. The U.S. Court of Federal Claims decides who will be paid damages for injuries that result from vaccines, under a 1988 law that created a program.

Another so-called “big” story from the last few weeks is the study on autism and thimerosal in Pediatrics, Prenatal and Infant Exposure to Thimerosal From Vaccines and Immunoglobulins and Risk of Autism. Sometimes when an important paper comes out (that I am aware of) I watch Google News as the embargo is lifted. I did so with this paper. Nothing happened. OK, I think Disability Scoop had a story out right at midnight (this one, if I recall correctly). Heck, it wasn’t until Friday that the CDC added the study to their website (it isn’t mentioned on the main cdc.gov webpage). Even SafeMinds (who are, in cases like this SafeBet–as in, it is a safe bet they will put out a critique of the paper) didn’t respond for days.

Sure, I was interested. And, yes, these stories sparked some of the most active conversations on this blog in a while. But I am still left with the basic conclusion: the general public has already absorbed these stories. The government conceded the Hannah Poling case 2 years ago. It isn’t new. The idea that mercury in vaccines cause autism–no longer part of the front line public discussion.

I’m not the only one to make this comment. The Washington Post had this to say four days after the paper was made public:

But when the journal Pediatrics published on Monday a study that found no increased risk of autism among more than 1,000 babies who’d been exposed prenatally or in the first 20 months of life to ethylmercury from vaccines, it was met with a general shrug. Neither The Washington Post nor The New York Times even reported on it, though the Los Angeles Times did, in its Booster Shots blog.

Sure, these stories will never completely go away. The vaccine/autism story will never go completely away. But the heyday is over.

Autism researchers want your input: Autism and the Internet at UCLA

18 Sep

Researchers at UCLA are interested in your input on a survey of Autism and the Internet. The study has IRB approval and the description from their site is below:

You are asked by Dr. Patricia Greenfield, of the Department of Psychology at the University of California, Los Angeles, if you would like to participate in this anonymous internet survey comparing how people with and without autism use the internet. Your participation in this study is voluntary and you may stop doing the survey at any point in time.

Purpose of the Research: The goal of this study is to see if the internet helps autistic and non-autistic people make friends and/or learn about their hobbies. We would also like to know if different ways of seeing the world, regardless of diagnosis, relate to different ways of using the internet.

Outline of Procedures: If you would like to participate in this study, please select the box at the end of this consent form titled “I consent to participate in the survey Autism and the Internet”. If you would not like to participate, select the box titled “I do not consent to participate in the survey Autism and the Internet.” If you consent to participate, the survey will appear on your computer screen. If you ever decide that you no longer want to complete the survey, you are free to stop taking the survey at any point in time. Your responses to the survey will remain anonymous. The survey will take between 15 minutes and one hour to complete.

Foreseeable Discomforts: Your may feel uncomfortable emotions when thinking about questions on the survey. If the survey questions make you feel uncomfortable, you are free to stop taking the survey at any point in time. The questions are designed to be as clear as possible so it is likely that you will not experience emotional discomfort as a result of the survey.

Potential Benefit to Participants and Society: Possible benefits of the study to society are that the knowledge gained may help people evaluate whether the internet helps autistic and non-autistic people to form connections and learn about their passions. This information may be useful in designing treatments to help autistic people communicate more effectively or in recognizing when such treatments are unnecessary because the autistic people are already satisfied with how they use the internet to communicate and learn.

Your participation would be anonymous and greatly appreciated. If you have the time and inclination, consider offering your experience to help out these researchers. The survey can be found here.

Autism researchers want your input: Autism Life Histories at Columbia

17 Sep

Prof. Peter Bearman’s group at Columbia has done and is still doing much in the way of autism epidemiology research. We have discussed many of his group’s papers here on LeftBrainRightBrain. Prof. Bearman’s group now has a website up, Understanding Autism.

As a part of their continuing research into autism, the Bearman team has launched a new project, AutismLifeHistories.org. This is essentially a survey to collect information from parents about their child’s

edit to add–here is how I intended that sentence to read
This is essentially a survey to collect information from parents about their child’s history, but nothing prevents a self-advocate from submitting information on him/her self.

The full description is below, but here is a shorter version from page 1 of the survey:

The purpose of this online survey is to learn about how you recognized your child’s autism, sought professional help and navigated the system of services. We hope that these stories help us arrive at a better understanding of the difficulties of the road to diagnosis and service provision.

While we do not believe that the content and the nature of the questions presented in this survey will cause you any discomfort, your participation is absolutely voluntary throughout the survey. This means that you are free to leave this survey at any time you wish. We will only read your responses if you complete and submit your responses.

It took me about 10 minutes. One could easily spend less.

Here is the longer description of the project:

Autism Life Histories
Dear Parent,

We are researchers at Columbia University’s Institute for Social and Economic Research and Policy studying autism. We are currently collecting life stories from parents about their experiences in recognizing their child’s autism, seeking professional help and navigating the system of services.

The goal of this project is to gain a better understanding of the road to diagnosis. Parents have different experiences and observations of their child’s development and they have different personal resources with which they access care and services. Parents also differ in the type and extent of their support networks and social relations. And finally parents make different decisions in their quest for obtaining the right diagnosis and care for their child. We are eager to hear about how these factors affected your experience and your child’s experience with autism.

We invite you to tell your story by completing a semi-structured survey in which your identity will remain confidential. In fact, this task is less of a survey and more of a conversation between you and us. There are three main sections to this conversation. The first section is set up to learn about you; we ask you a series of short questions. The second section is designed to learn about your child; we ask a series of short questions about his/her age, birth year and place and interaction with other children. The third section provides you with unlimited space to write about your story in recognizing your child’s autism. We hope you will decide to talk with us.

We thank you in advance for taking the time to read through this invitation and look forward to getting to know you. Please feel free to contact us via e-mail at understandingautism@columbia.edu with any questions that you may have. Please be assured that we will not share your story with anyone other than authorized members of our research team. No one else will have access to it.

To share your story, please click on the following link talk-to-us to the online survey.

Sincerely,

Peter Bearman, Principal Investigator
Cole Professor of the Social Sciences

Why are autistic people mainly male?

17 Sep

Excluding the ever humorous ideas of the Geier’s and more serious ideas of Simon Baron-Cohen regarding testosterone, the reasons as to why there are (or seem to be) many more autistic males than females have not been adequately explained. However that might be about to change.

A new study gives the first starting point as to why this situation might come about.

As we all know, males have an X and a Y chromosome whereas females have two X’s. This new study postulatesthat this fact plays an important role.

If a boy’s X-chromosome is missing the PTCHD1 gene or other nearby DNA sequences, they will be at high risk of developing ASD or intellectual disability. Girls are different in that, even if they are missing one PTCHD1 gene, by nature they always carry a second X-chromosome, shielding them from ASD…

The PTCHD1 gene is responsible for determining the development of human embryo’s and is already associated with autism. Because males only have 1 X chromosome, if this is defective then they – obviously – don’t carry that secondary level of shielding that females – with 2 X chromosomes – do.

However, this is very much preliminary. It should be noted that:

The researchers found that about one percent of boys with ASD had mutations in the patched domain containing 1 (PTCHD1) gene on the X-chromosome.

1% is not a very high number but as LBRB interviewee Stephen Scherer says:

The male gender bias in autism has intrigued us for years and now we have an indicator that starts to explain why this may be…

In other words, no one is saying this is a done deal – merely that its a strong possibility with some decent science behind it.

Autism causation and the Hepatitis B vaccine: no link

16 Sep

One of the primary subjects for those promoting vaccines as a primary cause of autism is the Hepatitis B vaccine. This vaccine is given at birth and represents a child’s first exposure outside the womb to a vaccine and, in the old days, to thimerosal. David Kirby attempted to link the rise in autism prevalence to the introduction of the HepB vaccine. Others have claimed that the rates of special education placements are 9 times higher amongst children given the HepB vaccine at birth. Here is the abstract for (Hepatitis B triple series vaccine and developmental disability in US children aged 1–9 years rel=”nofollow”)

This study investigated the association between vaccination with the Hepatitis B triple series vaccine prior to 2000 and developmental disability in children aged 1– 9 years (n¼1824), proxied by parental report that their child receives early intervention or special education services (EIS). National Health and Nutrition Examination Survey 1999–2000 data were analyzed and adjusted for survey design by Taylor Linearization using SAS version 9.1 software, with SAS callable SUDAAN version 9.0.1. The odds of receiving EIS were approximately nine times as great for vaccinated boys (n¼46) as for unvaccinated boys (n¼7), after adjustment for confounders. This study found statistically significant evidence to suggest that boys in United States who were vaccinated with the triple series Hepatitis B vaccine, during the time period in which vaccines were manufactured with thimerosal, were more susceptible to developmental disability than were unvaccinated boys.

The recent study on thimerosal and autism gives us a look at how the Hepatitis B vaccine might (or might not) be linked to autism. Exhibit 16.1 on page 82 of volume 2 of the technical report is a graph of HepB vaccine uptake among autistic children (AD) and non-autistic children (controls)

Here is that exhibit, showing the total number of vaccines (count) and amount of thimerosal (amt) for all vaccines and for HepB alone:

Price-HepBGraphs1-copy[1]

The top right graph shows the number of HepB vaccines for autistic kids (solid line) and non-autistic kids (dotted line). They are, to all intents and purposes, the same.

Take a look at the birth dose. Not every kid got it. Maybe about 1/2 got the birth dose at birth, and about 2/3 got it within the first few days.

If the birth dose of HepB caused autism to any significant degree, I would expect to see a higher percentage of autistic kids than non-autistic kids getting that shot. It just didn’t happen. Take a closer look at that graph:

Price-HepBGraphs2[1]

The same percentage of got the HepB shots–all 3 of them– as non-autistic kids.

Still wondering about that birth dose? Let’s zoom in on the graph:

Price-HepBGraphs3[1]

Those lines are right on top of each other.

The HepB hypothesis won’t go away. Just like the thimerosal hypothesis or the MMR hypothesis. Just today, Mark Blaxill and Dan Olmsted put out a very long post at the Age of Autism blog pushing the idea. They use the bad and worse studies from Thoughtful House on infant macaques to bolster their arguments.

The funny thing about evidence is, some people never accept it.

Further results from the thimerosal-autism study

14 Sep

The recent study on thimerosal and autism was extensive. Much data and many results were included in two technical reports (nearly 400 pages total, volume 1 and volume 2). I haven’t had the time to read them thoroughly yet, but I did catch some interesting pieces of information.

The authors give the ASD prevalence (cases/1000) as a function of HMO and year of birth:

This is pretty flat. No huge increase seen over that 6 year time span. No evidence for an “epidemic”. The prevalence is about 1.1%. This is consistent with the current value quoted by the CDC.

There are remarkably a big variation by parents educational status (63% kids born to mothers who graduated from college). However, since the researchers are working with kids who are enrolled in an HMO, it seems likely this is due to some bias. I.e. the HMO participants could be better educated (and higher income) than the average.

There are indications that increasing parental age is related to increased autism risk. 36% of mothers were in the 30-34 age bracket, 35% were in the 35+ age bracket. So, about 70% of mothers were over 30 years of age. They list father’s age with different brackets, but 79% were 30 years old or older at the time of birth of their child. Again, could be some bias due to HMO membership, but a large fraction of the parents were older.

Some children (both ASD and controls) received no vaccines. Many received vaccines but no thimerosal–i.e. all their vaccines were thimerosal free.

The use of prenatal vitamins is given as having an increased risk of autism, but the odds ratio is not given.

Being a first-born or second-born child has a significant increased risk for autism (hazard ratios of about 1.6). They may discuss this, but I don’t know right now how much of this is due to parents of autistic kids deciding not to have larger families.

One of the stranger results–there is an increased risk of autism when mothers were using prenatal vitamins with folic acid. The hazard ratio was 2.3 with a p value of 0.0176

Pica and childhood lead exposures had very high hazard ratios: 3.7. This is a good case where it is worth asking if this is causal–does pica cause autism or, as is more likely, does autism cause pica and, with it, higher lead exposures.

Poverty was slightly protective for autism (hazard ratio of 0.92). Again, one has to question if this is real or whether poverty just results in a greater likelihood that a child’s autism will be misdiagnosed.

The authors list coexisting conditions for the autistic, ASD and control children:

Epilepsy is much higher at about 5%, compared to 1.6% for controls. Reports of the prevalence of epilepsy amongst autistics are often much higher, though.

Developmental delay (by parent report) is at about 18% for autistics, compared to about 0.66% in controls.

Gi disorder prevalence is about 2% amongst autistics. It is the same (or slightly higher) for controls. This is very interesting given the anecdotal reports of a high prevalence of GI disorders amongst autistics. I suspect this will form some of the complaints about this study–some will say they aren’t looking at the correct population and that a specific study on autism/regression/GI complaints needs to be done.

Cases (those with ASD) were more likely to get thimerosal free HepB and HIB vaccines.

Infants in this study do not get flu vaccines (near zero). Unless that habit has changed dramatically in the past few years–and that most doctors are giving infants flu vaccines with thimerosal–flu vaccines are not likely to be a reason for the continued climb in autism prevalence.

There is a lot more information there. If/when I get the chance to give the reports a more thorough read I’ll post what I find.

Misfolding neural proteins

14 Sep

Regular readers might recall me blogging about neural proteins awhile ago. If I may quote myself:

…when the authors blocked APC function, they found that levels of the proteins neuroligin and neurexin dropped. So what…? Well, without these two proteins at normal levels, synapses grew improperly. So what…? Turns out that scientists already know that mutuations in the genes for neuroligin and neurexin are associated with autism…

And now along comes a new study that builds on this science.

Palmer Taylor, associate vice-chancellor for Health Sciences at UC San Diego and dean of the Skaggs School of Pharmacy and Pharmaceutical Sciences, and colleagues report that misfolding of a protein called neuroligin-3, due to gene mutations, results in trafficking deficiencies that may lead to abnormal communications between neurons.

Source.

So here we have a situation where genetic mutations leads to a misfolding of a protein that results in affecting the growth of synapses which in turn affects the development of autism.

Taylor said identifying and describing the misfolded protein link advances understanding of the complex causes of certain autisms, including the influences of genes versus environment…

Thats an interesting statement. I will try to get in touch with Taylor to explain that further.

← Older Entries
Newer Entries →