Awesomeness, thy name is…

13 02 2009

(No “Ignorance…” this week. This week’s winners are too awesome)

The U.S. Court of Claims. As you’ve probably seen, they recently ruled that there was no evidence whatsoever for a link between autism and vaccines, throwing out the three test cases, and by extension making it clear what the decision would be for the remaining 5,000 cases.

The special master in the Cedillo case said that,

“After a thorough review, I find that the evidence offered by respondent is substantially more persuasive concerning this issue.  I find that the evidence falls far short of demonstrating that it is “more probable than not” that thimerosal-containing vaccines can damage infants’ immune systems.”

Regarding the expert testimony of Dr. Jeffrey Brent,

“Dr. Brent did not dispute that mercury in some of its forms, at certain dosages, can be toxic, or even fatal, to humans.  But he stressed that Dr. Aposhian was inappropriately relying on instances of mercury toxicity involving mercury in forms quite different from the ethylmercury found in thimerosal, and  on instances involving exposure to vastly greater amounts of mercury than the small amounts used as preservatives in vaccines.

As to the forms of mercury, Dr. Brent explained that the many different types of mercury have toxological properties quite different from one another, so that it is inappropriate to generalize, as Dr. Aposhian does, from one form of mercury to another.

[…]

Dr. Brent also testified that Dr. Aposhian’s causation theory erroneously ignored the “dose- response” principle, a foundation of medical toxicology.  Dr. Brent explained that almost any substance can be toxic if administered in high enough quantities, while substances that are toxic at high doses can be harmless or even beneficial at low doses.”

Regarding “genetic hypersuceptibility” :

Petitioners have suggested that there may exist a group of humans who, unlike most humans,are genetically “hypersusceptible” to mercury, leaving them vulnerable to immune system damage when exposed to ethylmercury.  Dr. Aposhian’s testimony seemed to assert this theory.  (Tr. 92, 115, 129-131.)  After review, however, I find that petitioners have failed to demonstrate that this theory has any validity. First, neither Dr. Aposhian nor any other of petitioners’ experts pointed to any scientific research  that even suggests that such “hypersusceptibility” exists.

Mercury efflux disorder:

Dr. Aposhian testified  that autism in some individuals, perhaps including Michelle Cedillo, may be caused by a “mercury efflux disorder,” meaning that the child is unable to excrete mercury as efficiently as most children do, and a resulting build-up of mercury in the body damages the function of the body’s cells, including cells in the immune system.

[…]

Dr. Brent, however, testified effectively that petitioners’ “mercury efflux disorder” theory is highly dubious.  (Tr. 2351-63.)  He noted that such a disorder is not recognized by the medical community.   (Tr. 2361-62.)  He also pointed to severe problems with the studies on which Dr. Aposhian principally relied for his “mercury efflux disorder” theory, the Holmes  and Bradstreet 2003  studies.

In the Holmes study  (Ex. 55, Tab X), the investigators measured the mercury levels in the hair of autistic children and non-autistic “control” children, and found lower levels in the autistics, which led them to suggest that autistics may have a problem in excreting mercury.  Dr. Brent, however,  testified that the results and conclusions of the Holmes study failed to make sense for a number of reasons.  (Ex. L, pp. 19-21; Tr. 2351-54.)  Among those reasons was the fact that the mercury hair levels found in the autistic individuals tested by Holmes actually were squarely within the normal range of what other testing indicated would be the normal level of mercury in hair in U.S. children.  (Ex. L, pp. 19-20; Tr. 2351-53.)  Dr. Brent explained that the Holmes investigators’ conclusion, that the autistics had abnormally low levels of mercury in their hair, was caused by the fact that the non-autistic children used as “controls” in the study, for some unexplained reason, had hair mercury levels about 15 times the normal rate found in a previous huge study of American children’s hair.  (Ex. L, p. 20; Tr. 2350-51.)  Dr. Brent found that this unexplained deviation from the prior accepted mercury hair level data made the Holmes study extremely suspect.

Dr. Brent explained further that when two other groups of researchers performed studies similar to the Holmes study, both found no significant differences in the mercury hair levels between the autistics and controls studied.  (Ex. L, p. 20; Tr. 2462-66.)  I find that at least one of those studies, the Kern study,  supports Dr. Brent’s testimony in that regard.

He also discounted another study which Dr. Aposhian had described as supporting the Holmes study.  Dr. Brent stated that this study, the Hu study,  involved only three autistic individuals, and suffered from the same grave problem as the Holmes study–i.e., the mercury hair levels in the autistics were actually precisely that which would be expected in average, non-autistic American children.

Dr. Brent also criticized the other study upon which Dr. Aposhian chiefly relied, the Bradstreet 2003 study.  In that Bradstreet study, urinary mercury excretion was measured in groups of autistic children and non-autistic “control” children, after the subjects underwent a process known as “chelation.”  The authors reported higher mercury concentrations in the urine of the autistics, concluding therefrom that autistic children have a decreased ability to excrete mercury.  Dr. Brent, however, explained that the study suffered from so many methodological and conceptual errors that it essentially provided no useful information whatever.  (Ex. L, pp. 21-22; Tr. 2356-61.)  As one example, he noted that urinary excretion following chelation has been shown to be an inaccurate measure of mercury body burden.  (Ex. L, p. 22.)  He also noted that the way in which the controls were selected for the study was problematic.  (Ex. L, p. 22; Tr. 2358.)  Additionally, Dr. Brent testified that the study authors made a major mistake in failing to measure the urinary mercury levels in individual subjects  prior to chelation (Tr. 2359-60), and even Dr. Aposhian himself acknowledged that he would have done the study differently in that regard (Tr. 166).  Dr. Brent described problems with the statistical methodology that the study authors used.  (Ex. L, p. 22; Tr. 2358.)  He also stated the Bradstreet 2003 study was published in a “fringe” medical journal.   (Tr. 2360.)  Finally, Dr. Brent noted that another research group performed a study similar to Bradstreet’s, but without the methodological flaws, and published it in a “legitimate” medical journal.   (Id.)  That study, in contrast to Bradstreet’s, found no difference between autistics and controls in urinary mercury levels after chelation.  (Tr. 2360-61.)

I’ve already cleared the 1,000 word mark, so I’ll stop there. You get the idea. If you want to read the full decision, it (and the other two) can be found here: http://www.uscfc.uscourts.gov/autism-decisions-and-background-information

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