Monday, November 23, 2009

The Environment and ADHD

A new study was published in Pediatrics today that deals with one of the other major childhood disorders, ADHD.  According the this study, a child is more likely to develop ADHD if they have prenatal exposure or childhood exposure to lead.  I have not read the study yet, but from the press it is getting it seems this is a result is going to be an important one -

Association of Tobacco and Lead Exposures With Attention-Deficit/Hyperactivity Disorder
METHODS Data are from the 2001–2004 National Health and Nutrition Examination Survey, a cross-sectional, nationally representative sample of the US population. Participants were 8 to 15 years of age (N = 2588). Prenatal tobacco exposure was measured by report of maternal cigarette use during pregnancy. Lead exposure was assessed by using current blood lead levels. The Diagnostic Interview Schedule for Children was used to ascertain the presence of ADHD in the past year, on the basis of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria.
RESULTS A total of 8.7% (95% confidence interval [CI]: 7.3%–10.1%) of children met criteria for ADHD. Prenatal tobacco exposure (adjusted odds ratio [aOR]: 2.4 [95% CI: 1.5–3.7]) and higher current blood lead concentrations (aOR for third versus first tertile: 2.3 [95% CI: 1.5–3.8]) were independently associated with ADHD. Compared with children with neither exposure, children with both exposures (prenatal tobacco exposure and third-tertile lead levels) had an even greater risk of ADHD (aOR: 8.1 [95% CI: 3.5–18.7]) than would be expected if the independent risks were multiplied (tobacco-lead exposure interaction term, P < .001).
CONCLUSIONS Prenatal tobacco and childhood lead exposures are associated with ADHD in US children, especially among those with both exposures. Reduction of these common toxicant exposures may be an important avenue for ADHD prevention.
Edited to add : Here is a good write up of this study.

Alternative Autism Treatments and Mad Cow

Flickr Photo by
Twenty Questions

The Chicago Tribune has yet another article today attacking the use of alternative medicine in treating autism.  While the journalists do have some valid points, the general tone of the articles are troubling.  There are alternative autism treatments that do have value and can be effective and lumping all alternative treatments into the junk category is simply dishonest.

To illustrate what I am talking about, I would like to (unfairly) highlight one passage from one of today's articles -
Intravenous immunoglobulin, or IVIG, consists of pooled antibodies separated from the plasma of multiple donors. Its serious side effects run from fevers and headaches to anaphylactic shock and meningitis. Blood is screened, but there is still a remote risk of contracting some diseases, including "mad cow" disease.
So, from this you would infer that IVIG is a dangerous procedure - one that could give you some horrible disease like "mad cow", right?


I cannot find a single documented case of anyone ever contracting "mad cow" from IVIG.  As a matter of fact, the blood supplies used for IVIG are very well screened to prevent this sort of thing from happening -
Being a human product made from blood donations by many people, IVIG can transmit disease. IVIG available in the United States is very carefully screened to be free of all known transmissible diseases, including HIV, hepatitis, malaria, syphilis, and many, many others. However, as with blood transfusions, there is always a risk that the product contains an infection that has not yet been recognized -- either because it is a previously unknown disease or because a donor's infection was so early that his or her blood gave no clues.
To put this in perspective, American blood products are the safest in the world. Very, very few people have every gotten an infection from IVIG. However, in the past 30 years, IVIG has been temporarily removed from the market three times -- each time to test it for a newly recognized disease (HIV, hepatitis C, "mad-cow disease") that had not been excluded before the IVIG had been released to the public. In fact, IVIG did not carry these diseases and no one actually got sick because of the having received IVIG. However, no one can guarantee that a new disease will not appear tomorrow that will not have been yet tested for.
Don't take my word for it, look into the safety of IVIG for yourself.  And if you are thinking of using a treatment like this on your child, you should most definitely research it yourself..

This is a perfect example of what is wrong with this sort of reporting.  Reasonable people can disagree about whether a particular treatment, such as IVIG, is appropriate, for treating autism.  But when you bring this sort of sensationalism into the picture - such as statements implying that IVIG is going to give your child mad cow - all you are left with is nonsense.

Saturday, November 21, 2009

Dr Offit may not like basements

Flickr Photo from nic0
I am starting to think that Dr Offit doesn't like basements.   That must be the reason why Dr Offit doesn't  like to publisize his relationship with the Autism Science Foundation (ASF).

You would think that it is a match made in heaven.  Dr Offit knows that there is no relationship between vaccines and autism and the entire mission of the Autism Science Foundation is to fund all autism research except that which has anything to do with vaccines.  And as a matter of fact, Dr Offit is on the board of directors for the Foundation.

Yet Dr Offit doesn't seem to like to talk about the Foundation that he helps direct.  If you look at his recent press (and he does seem to like his publicity) such as Newsweek, Wired, Pediatric SuperSite, New York Times, or the Op-ed page of the New York Times  you won't find any mention of a relationship.  If you look at the resume on his site, it isn't mentioned either.

There even isn't any mention on his Wikipedia page.

I have no idea why Dr Offit doesn't like to talk about his relationship with the Autism Science Foundation.  This is the organization that hopes to one day replace Autism Speaks as the premier autism organization so you would think that the he would do whatever he could to help its mission.  About the only thing that I could think of is the Foundation is run out of Allison Singer's basement and Dr. Offit must not like basements.

After all, the good doctor is very concerned about the welfare of children who have autism and spends much of his time treating them and trying to help them, right?  Oh wait, I must be thinking of someone else.  Dr. Offit doesn't have anything to do with autism other than to say that vaccines didn't cause it.

Why is he on the board of directors of the Autism Science Foundation again?

Wednesday, November 18, 2009

Newsweek panders to Dr. Offit

Dr. Offit has written a short blurb for Newsweek's Top 10 list of "Most Overblown Fears" of the decade.  It is filled, as would be expected, with half truths and distortions.  And of course, like most major media outlets, Newsweek has failed to mention the fact that Dr. Offit has made a fortune from his patent on the Rotateq vaccine.  So, if you care to read yet another version of the classic "asked and answered" line, have at it.

For me, there are two lines from the piece that stand out.  The first is -
As is true with most pseudoscience, hypotheses shift, eventually settling on one that isn’t testable and, therefore, can never be proven wrong
This idea that "shifting hypotheses" is somehow unscientific is completely absurd on its face.  The bedrock of modern science is the scientific method where the whole idea is that you come up with a hypothesis, test it, and if doesn't pan out you come up with a new hypothesis and test that one.  Lather, rinse, repeat as needed.

Yet coming up with an alternative hypothesis to fit the available facts is somehow pseudoscience?

Anyway, the second line is -
The tragedy is, given all we now know about the neurological basis of autism, all three of these hypotheses had no chance of bearing fruit.
Apparently Dr Offit knows something that the rest of us don't because, as far as I am aware, the amount we "know" about the physiological basis of autism amounts to almost nothing.

We don't "know" what causes autism, we don't know how autism effects the brain, we don't know the biological basis of autism, we don't have any sort of biological marker for autism, nor do we even know what autism is.  So how exactly can we say that there is "no chance" of any theory bearing fruit when we don't have the slightest clue what we are even talking about?

I expected this sort of nonsense from Dr. Offit but I had more respect for Newsweek.  I guess it is time to cancel my subscription.

Thursday, November 12, 2009

Bad science might be genetic

Flickr Photo from
Chemical Heritage Foundation

If you give a kid a new toy they are going to want to play with it.  Never mind the heaps of older toys they they have, those are yesterday's toys and not worth even considering.  In a similar vein, scientists now have the tools to look at a person's genetic code more closely than they ever have in the past, and they have just got to play with them.

As a case in point, consider the article "Bad Driving May Have Genetic Basis, Study Finds" on Science Daily.  A group of researchers looking at a genetic variant that may play a role in memory decided to give a driving test to a group of 29 people.  There were seven people with this genetic variant in this group and the researchers found that  -
People with a particular gene variant performed more than 20 percent worse on a driving test than people without it -- and a follow-up test a few days later yielded similar results. About 30 percent of Americans have the variant.
So there you have it, the new toys have been used and have decreed that people with this particular genetic variant are worse drivers.  It isn't something they can help, after all, its genetic.

Only, I have to wonder, can this really be the case?  I went and found the study that this article was based on but since I refuse to pay 36 dollars for something like this I am only going what the abstract says and the article on Science Daily.

So I ask myself, what does this gene supposedly do?
This gene variant limits the availability of a protein called brain-derived neurotrophic factor during activity. BDNF keeps memory strong by supporting communication among brain cells and keeping them functioning optimally. When a person is engaged in a particular task, BDNF is secreted in the brain area connected with that activity to help the body respond.
Got that?  A protein plays a role in in keeping memories strong by strengthening the connections between brain cells.  This genetic variant is "limits the availability" of the protein which in turn might have an affect on memory which somehow translated into worse driving skills.  This result is already two thirds of the way to Kevin Bacon

I have to wonder if the researchers have ever heard of the concept of confounding factors.  In a sample of 29 people, isn't it more likely that some (or maybe even most) of group are simply bad drivers?

But wait, it gets even better. The researchers even got to use one of the coolest new toys around, an fMRI  -
Functional magnetic resonance imaging (fMRI) scanning during right index finger movement (n = 24) identified activation in a broad sensorimotor network. However, subjects with the polymorphism showed smaller activation volume within several brain regions as compared with subjects without the polymorphism.
So remember, if your brain doesn't light up as much when you twitch your finger, you might have a genetic variant that makes you a bad driver. It couldn't be that being a bad driver makes you a bad driver, there always has to be a genetic reason nowadays.

Kids and their toys.

Wednesday, November 11, 2009

Damaging DNA without touching it

Photo from berkeleylab (flickr)
This post is going to be somewhat off-topic from autism but this is something that I thought was interesting and could potentially one day have implications for some of the mysterious health problems like autism.
There is a study entitled "Nanoparticles can cause DNA damage across a cellular barrier" in the November 5th issue of Nature Nanotechnology that demonstrated that nanoparticles could, under laboratory conditions, cause damage to the DNA of cells that they couldn't touch.

Now, if you are like me and have only a rudimentary understanding of molecular biology then most of what the this study says will be indecipherable jargon.  Lucky for us, there is an article at The New Scientist that explains the results in easier to understand terms.

In simple terms, there were three items in a lab dish - a group of nanoparticles, a barrier made up of human cells that have been specialized for lab work, and a type of human cell (fibroblast) that is found in skin and connective tissue.  The nanoparticles were physically separated from the fibroblast cells by the barrier cells.

Yet, after a day in the lab dish, the fibroblast cells had damage to their DNA, presumably from the nanoparticles.  The New Scientist explains what might have happened -
The nanoparticles directly influenced the nearest layer of barrier cells and disrupted their mitochondria – chambers where energy is generated and stored.
That released signalling molecules – mainly the energy-transport molecule adenosine triphosphate (ATP) – which in turn triggered a cascade of biochemical messages inside the cell. That signalling storm eventually reached the other side of the barrier cell, opening channels that spread the message to the next layer of barrier cells.
This Chinese-whispers process continued until signalling molecules reached the fibroblasts, somehow damaging their DNA – the researchers don't yet know how this happened.
Or in a nutshell, the nanoparticles somehow disrupted the mitochondria of the barrier cell which in turn caused  damage to the DNA of the other cells.   The setup from this experiment is completely made-up and does not resemble anything that can occurs in the human body.  But at the same time, I did not realize that something like this was even possible.   It will be interesting to see if this result can be confirmed by other groups.

I don't think that this scenario in this experiment has anything directly to do with autism, nor do I think that nanoparticles have any sort of causal role in autism.  But, I have to wonder if there could be a mechanism similar to this that happening in some people with autism.  So far, studies that have looked for a genetic cause to autism have only found very small groups that share any sort of common genetic changes.  And the majority of these findings have failed to be replicated by other groups.  Perhaps the reason for this is that we have cause and effect wrong.  Perhaps these small genetic changes are not the cause of autism but rather the effect of another process that causes autism.

Just food for thought.