Post a Comment On: Adventures in Autism

The CDC truly has no shame.

They didn't even include autistic children in this study. How much you wanna bet that dispite this fact, we will be reading media headlines that say, "new CDC study proves that vaccines not linked to autism".

[Update: That didn't take long. "New Study Results: Vaccines Not Tied to Autism"]

Exclusion of low birth weight babies, 70% participant drop out rate, focusing on blood mercury levels and ignoring brain mercury, conclusions not backed up by the data, conflicts of interests with all the researchers and on and on...

It is like a greatest hits of all the bad research done in the last decade wrapped up in one convenient package.

This thing looks to be Verstraeten all over again.

Thanks to A-CHAMP for the heads up.

Dear A-CHAMP subscribers:

On September 27, 2007 the New England Journal of Medicine will publish a study entitled, "Early Thimerosal Exposure and Neuropsychological Outcomes at 7 to 10 Years." For more than two years we at A-CHAMP have been hearing rumors of a new study that "exonerates" thimerosal, despite the fact that the study results were supposed to be kept strictly confidential.

Now the rumors have been turned into hype - another government funded study that tries to spin data and clear thimerosal of any suspicion of causing neurodevelopmental disorders. The study authors claim in their "Conclusions" that "[o]ur study does not support a causal association between early exposure to mercury from thimerosal-containing vaccines and immune globulins and neuropsychological functioning at the age of 7 to 10 years."

The statement is plainly false. The study's conclusions do not reflect the study's data or the limitations of the study,

Unfortunately we have come to expect misleading statements – some might say fraudulent statements – from studies emanating from the CDC and their associates. It is not merely the fact that the authors of the study are burdened by large conflicts of interests - almost all of the 18 study authors have worked for vaccine manufacturers, received money from them, or performed research on their behalf. What is truly shocking about this study is that it does, indeed, find significant associations between thimerosal-containing vaccines and tics, speech, executive functioning and attention, but irresponsibly dismisses the associations. The study did not even look at children with autism – that is the subject of another uncompleted study – and children who might be more vulnerable to mercury, like low birth weight babies and children from families with lower incomes, were excluded or under-represented in the study sample

Fortunately, an advocate from our own community was an external consultant to the study, participated in its development from the outset, and is intimately familiar with the data and methodology. She has dissented from the study's conclusions. In addition, our colleagues and fellow parents at SafeMinds will be issuing a critique of the study in the near future. We are also told that the study data will be made publicly available so that independent researchers may examine it and draw their own conclusions.

Although detailed analysis of the study is beyond the scope of this letter, below are some key points that cause us to distrust this study as another attempt to manipulate the scientific and public debate on thimerosal to the detriment of the health and safety of America's children:

1. The Study's Claim of No Causality is Contrary to the Study's Data

The study authors claim that the data disproves causality when in fact, several findings show a negative effect on neuropsychological functioning warranting more study. At least one such adverse association was also found to be associated with low dose thimerosal exposure in other studies. As with earlier studies hyped by vaccine promoters, the study is unable to prove or disprove causality. The blanket dismissal of the troubling neuropsychological outcomes in this study is disingenuous and misleading.

2. Children with autism were excluded from this study

The early media contacts we have received suggest that this study shows no association between thimerosal and autism. In fact, the study specifically did not look at children with autism as the sample size was too small and the testing is impossible to complete for the typical child with autism. The exclusion of children with autism from the study may have undermined the power of the study to draw any conclusions about thimerosal.

3. The Study's Authors Misrepresent Previous Toxicokinetic Studies of Thimerosal

The study authors falsely claim that research by Burbacher et al. at the University of Washington (distribution of thimerosal as compared with methylmercury in infant monkeys) shows that ethylmercury is safer than methylmercury. But the authors focus only on the blood "half-life", ignoring data, showing twice as much inorganic mercury trapped in the brains of monkeys than from same dose of methylmercury.

4. The Study's Methodology has Serious Limitations Negating Any Conclusions Drawn

Major flaws that that causes a large underestimation of neurological adverse effects burden the study: 70% of the families recruited for the study failed to participate. This kind of bias in epidemiological studies is well known to distort even large studies of health effects. (See , for example, NY Times Magazine, "Do We Really Know What Makes Us Healthy" by Gary Taubes 9/16/07). It is well established that people who choose to participate in this kind of study are probably very different than those who refuse to participate (the "healthy person" or "complier" effect); especially when the ones who refused to participate said they were too busy.

Simply put: if you have a kid with ADHD or mild ASD or other neurodevelopmental disorders, you are likely to be busier, more stressed, and less available than the mother of a healthy normal child. This phenomenon serves to amplify the effect of the "complier", the "healthy families," - those who do cooperate with the study - confounding or confusing the study's results. The cooperative parents included in the study were more likely to be those with relatively trouble-free kids

5.Major Conflicts of Interest Burden Almost Every One of the 18 Study Authors

Many of the study authors have either worked for or received money from vaccine manufacturers. Others are employed by the CDC, which has been criticized by an IOM committee for its inherent conflict of interest in promoting vaccines while simultaneously monitoring safety. Many of the remaining study authors have conducted studies for vaccine manufacturers. The conflicts of interest cast doubt on the validity of the study, especially of the clearly biased final conclusions.

6. The High & Low Thimerosal Exposure Groups Too Small to Draw Conclusions

In addition to the number of children of the study being too small to draw statistically significant conclusions, the numbers of children in the high exposure group and the low exposure group were far too small to draw conclusions. Yet the study ignored this limitation and drew sweeping conclusions of no causality.

7.Vulnerable Children Were Excluded from the Study; Early Intervention Was Ignored

Children with a birth weight under 5 lbs. 8 oz. were excluded from the study further skewing the results, as these children are likely more vulnerable to thimerosal than larger babies. In addition, the fact that early intervention may have reduced deficits such as speech delay detected by neuropsychological testing of children aged 7-10 was not accounted for in the study results. There also was no analysis of combined prenatal and postnatal mercury exposures. Only 103 mothers who were exposed to mercury from prenatal immune globulins participated in the study, far too small a group for researchers to draw conclusions regarding the safety of thimerosal in these products.

8. The Study Fails to Account for the Subset of Children with "Efflux Disorder"

Only approximately 1000 children participated in the study, out of more than 3000 that were recruited. In addition to the "complier" bias discussed above, the study sample size is too small to accurately estimate the adverse effect of Thimerosal on the subset of the population who have a problem in mobilizing and excreting mercury. While the study's author's focus on the average time it takes for mercury to clear from the blood, itself misrepresented, we know that in 15% of the population this average is greatly exceeded. It is these children who are vulnerable to the effects of mercury from thimerosal. This study fails to account for the effect of mercury from vaccines on this subset of children.

These are but a few of the serious problems with the study and the way the data have been presented. We look forward to the forthcoming SAFEMINDS critique of the study and thank them for their continued close monitoring and analysis of the scientific research that affects our children.

In the meantime, if you see headlines stating that "Vaccines Cleared in New Study" or "New Study Finds Thimerosal Safe" know that we are all again being played, and that those who we should be able to trust are compromising the truth and the health of our children.

Sincerely,
Bob Krakow, for A-CHAMP