Smarter People More Susceptible to Heavy Metal Toxicity?
On Autism Mercury, Andrew Hall Cutler wrote that he suspects intelligence plays a role in heavy metal poisoning:
To understand his point, assume there is a normal distribution (or bell curve) of intelligence among a subset of children with the same level of lead in their blood. In other words, take a vertical slice of the graph - this is your bell curve at that blood-lead level.
An obvious assumption is that as the blood level of lead increases, intelligence will decrease in direct proportion. If this was the case, the bell curve should exhibit a linear change as you move to the right on the graph.
In other words, the top and bottom "edge" formed by the bell curves as you move to the right should be linear.
However the figure shows that it is not.
The cluster of dots gets tighter as you go to the right, due to the top half been "squeezed" down. The top edge decreases very quickly with increasing lead - it shows an obvious curve which indicates a non-linear relationship. But the bottom edge barely decreases, and is roughly linear.
This is the effect noted by Andrew Hall Cutler - that children with higher intelligence seem to be more affected by increased lead than children of lower intelligence. And as he notes, this effect is not really explained by the authors of the paper.
... the dirty little secret that is peeking out here is that smart people are more susceptible to heavy metal toxicity than ones of lesser intelligence. Lead dumbs them down, mercury makes them crazy. There are hints of this in journal literature data, though the authors work mightily to not notice it.When asked for more information, he provided a journal article reference from Environmental Health Perspectives, Volume 112, Number 9. The article, Recent Developments in Low-Level Lead Exposure and Intellectual Impairment in Children) is here [PDF format]. The figure he mentions is on page 5.
To understand his point, assume there is a normal distribution (or bell curve) of intelligence among a subset of children with the same level of lead in their blood. In other words, take a vertical slice of the graph - this is your bell curve at that blood-lead level.
An obvious assumption is that as the blood level of lead increases, intelligence will decrease in direct proportion. If this was the case, the bell curve should exhibit a linear change as you move to the right on the graph.
In other words, the top and bottom "edge" formed by the bell curves as you move to the right should be linear.
However the figure shows that it is not.
The cluster of dots gets tighter as you go to the right, due to the top half been "squeezed" down. The top edge decreases very quickly with increasing lead - it shows an obvious curve which indicates a non-linear relationship. But the bottom edge barely decreases, and is roughly linear.
This is the effect noted by Andrew Hall Cutler - that children with higher intelligence seem to be more affected by increased lead than children of lower intelligence. And as he notes, this effect is not really explained by the authors of the paper.
(c) 2005 Copyright Onibasu.com. You may copy and distribute the text of this blog for non-commercial purposes as long as you give credit and provide a link back to the original blog. All other rights are reserved.
0 Comments:
Post a Comment
<< Home