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Cochrane review: no clinical trial evidence was found to suggest that pharmaceutical chelation is an effective intervention for ASD

10 Sep

Chelation was never used by the majority of parents on their autistic kids. And that is a good thing. Chelation use is way down in the autism communities, but it hasn’t gone away. Many of those who use chelation are also vaccine antagonistic, and many of those rely upon the Chochrane reviews to support their vaccine-antagonistic arguments (generally by cherry picking and misrepresenting the Chochrane reviews). So, I was intrigued when I saw this abstract come up recently: Chelation for autism spectrum disorder (ASD).

A Chochrane team looked at the evidence for chelation and found that there is none.

A while back there was a plan for a chelation trial at the National Institutes of Health. It was cancelled when animal studies found a drop in cognitive scores when chelation was used without heavy metal intoxication. Which is to say, if you chelate someone needlessly, you could be shaving off IQ points. And since there is no evidence that autism is a form of heavy metal intoxication, chelation may actually have been harming already disabled kids.

I bring this up because the Chochrane review mentions a possible clinical trial in their last abstract sentence: “Before further trials are conducted, evidence that supports a causal link between heavy metals and autism and methods that ensure the safety of participants are needed.”

Yeah, I know that teams of people with MBA’s and other non-related degrees will tell you that there is evidence. As will doctors who sell chelation. Or recommend it (Hello, Dr. Bob Sears, I’m talking to you and your community of non-autism docs). They are wrong. And potentially harming autistic children.

Here is the abstract

Abstract
BACKGROUND:
It has been suggested that the severity of autism spectrum disorder (ASD) symptoms is positively correlated with the level of circulating or stored toxic metals, and that excretion of these heavy metals, brought about by the use of pharmaceutical chelating agents, results in improved symptoms.
OBJECTIVES:
To assess the potential benefits and adverse effects of pharmaceutical chelating agents (referred to as chelation therapy throughout this review) for autism spectrum disorder (ASD) symptoms.
SEARCH METHODS:
We searched the following databases on 6 November 2014: CENTRAL, Ovid MEDLINE, Ovid MEDLINE In-Process, Embase,PsycINFO, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and 15 other databases, including three trials registers. In addition we checked references lists and contacted experts.
SELECTION CRITERIA:
All randomised controlled trials of pharmaceutical chelating agents compared with placebo in individuals with ASD.
DATA COLLECTION AND ANALYSIS:
Two review authors independently selected studies, assessed them for risk of bias and extracted relevant data. We did not conduct a meta-analysis, as only one study was included.
MAIN RESULTS:
We excluded nine studies because they were non-randomised trials or were withdrawn before enrolment.We included one study, which was conducted in two phases. During the first phase of the study, 77 children with ASD were randomly assigned to receive seven days of glutathione lotion or placebo lotion, followed by three days of oral dimercaptosuccinic acid (DMSA). Forty-nine children who were found to be high excreters of heavy metals during phase one continued on to phase two to receive three days of oral DMSA or placebo followed by 11 days off, with the cycle repeated up to six times. The second phase thus assessed the effectiveness of multiple doses of oral DMSA compared with placebo in children who were high excreters of heavy metals and who received a three-day course of oral DMSA. Overall, no evidence suggests that multiple rounds of oral DMSA had an effect on ASD symptoms.
AUTHORS’ CONCLUSIONS:
This review included data from only one study, which had methodological limitations. As such, no clinical trial evidence was found to suggest that pharmaceutical chelation is an effective intervention for ASD. Given prior reports of serious adverse events, such as hypocalcaemia, renal impairment and reported death, the risks of using chelation for ASD currently outweigh proven benefits. Before further trials are conducted, evidence that supports a causal link between heavy metals and autism and methods that ensure the safety of participants are needed.


By Matt Carey

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