Thursday, November 17, 2016

Time for a change

Sandra M. Pinkham, M.D<   Time for  A Change
. 11-17-2016
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 Since lead was taken out of gasoline in 1980, the public has been told that lead is the most serious toxic agent. Flint Michigan parents were told that their children were being permanently damaged by exposure to lead in water.  The public has been old that removing lead from gasoline which lowered blood lead levels dramatically has made the air cleaner. What is wrong with this message?   
In the last 30 years I have made an extensive search of the world literature on lead and cadmium and other toxic substances known to have an adverse effect on health. This was triggered by a finding in a hair analysis study that I did on children in 1986. The children in my study with the highest levels of lead and cadmium in their hair had the lowest scores on achievement. This was statistically significant for lead but not cadmium.  All the children were exposed to cadmium from a large waste incineration plant in operation for 2 years, a very significant source of cadmium pollution and other chemicals that act in synergy with cadmium. Only 2 of the 60 were exposed to passive smoke, another very significant source of cadmium air pollution exposure in humans.  The children with the higher levels of lead and cadmium were experiencing stress from having learning problems. The hair lead levels were associated with very low levels of blood lead. The children had minimal exposure to lead. Although the cadmium levels were elevated in the children with learning problems, the high variability in hair cadmium compared to hair lead resulted in an insignificant statistical correlation.
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From my literature search, I discovered that it is the  statistical correlation of small elevations of blood leads at any level along the line from a blood lead of 20 ug/dL to zero that is the main proof that lead is so toxic. In studies where lead is given for long periods of time to show adverse effects in experimental animals, there was no attempt to see what happens to other metals, especially cadmium in most studies. In the few where that was studied researchers showed that ingestion of lead in water increased cadmium uptake into the brain.  Just the fact that when blood lead levels averaged 15 the toxic children had blood lead levels of 20 and when the average was 5 the toxic children had 10 and now when the average blood lead level is less than one a blood lead level of 5 is considered toxic should make one suspicious that lead exposure may not be the cause of the linear correlation. .  Clearly all the children in the 1960’s and 70s were not being poisoned by lead.

 An alternate explanation which makes more sense is that blood lead is not just an indicator of exposure. Small increases over a background level is actually an indicator of a toxic effect that is increasing the presence of lead ions in blood. My next blog will explain the biochemical basis for this effect.

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