A 'Silent Pandemic' Of Brain Disorders
Exposure to industrial chemicals may be responsible for a "silent pandemic" of brain development disorders affecting millions of children worldwide, and not enough is being done to identify the risks.
That is the contention of two researchers who have studied the effects of chemical exposures on brain development for many decades.
In an essay published online in the journal The Lancet, the researchers identified 202 potentially harmful industrial chemicals that may be contributing to dramatic increases in autism, attention deficit hyperactivity disorder (ADHD), and other brain disorders among children.
Roughly half of the chemicals are in common use, but very few have been tested to determine their impact on brain development.
"The bottom line is you only get one chance to develop a brain," Philippe Grandjean, M.D., of the Harvard School of Public Health, tells WebMD. "We have to protect children against chemical pollution because damage to a developing brain is irreversible."
Tip of the Iceberg
Grandjean and co-author Philip Landrigan, M.D., of New York's Mount Sinai School of Medicine, noted that of the industrial chemicals known to be toxic to the human brain, only five — lead, mercury, arsenic, PCBs, and toluene — have been proven to cause damage to the developing brain.
These chemicals have been identified not because they are necessarily more dangerous than the others, but because they have been studied the most, Grandjean and Landrigan contend.
"The few substances proven to be toxic to human neurodevelopment should be viewed as the tip of a very large iceberg," they wrote.
Grandjean spent decades documenting the toxic effects of mercury exposure on the developing brain, and Landrigan spent decades studying the effects of lead exposure in children.
Lead and mercury are among the few chemicals that are now strictly regulated to protect children. But regulation came long after the dangers were first recognized.
Lead-based paint was first linked to sickness in children more than a century ago, but lead was not removed from paint and gasoline in the U.S. until the late 1970s and early 1980s.
"Despite those early pediatric warnings, the largely unchecked use of lead in petrol, paints, ceramic glazes, and many other products through much of the twentieth century caused continued risk of lead poisoning," the researchers write.
A Generation Exposed
Almost all children born in industrialized countries between 1960 and 1980 were exposed to substantial amounts of lead from gasoline. The researchers write that lead exposure in this population could be responsible for a substantial reduction in average IQ scores.
"A generation of American children was exposed to this very dangerous neurotoxin while we were doing traditional risk assessment," Grandjean tells WebMD. "We can't afford to make the same mistake again."
Annette Kirshner, Ph.D., of the National Institute of Environmental Health Sciences (NIEHS) agrees that more expeditious ways of identifying chemical exposures that put children at risk are needed.
The prevailing thinking among researchers studying autism and ADHD is that both genetic and environmental factors play a role in the childhood brain disorders.
"There is still no good evidence linking any single environmental exposure to autism and ADHD," Kirshner tells WebMD. "It will probably require a global effort to understand the combination of factors that lead to these disorders."
But Grandjean and Landrigan argue that exposure to industrial chemicals appear to have created a "silent pandemic in modern society."
"Although these chemicals might have caused impaired brain development in millions of children worldwide, the profound effects of such a pandemic are not apparent from available health statistics," they wrote.
By Salynn Boyles
Reviewed by Louise Chang
© 2006 WebMD, LLC.. All Rights Reserved. That is the contention of two researchers who have studied the effects of chemical exposures on brain development for many decades.
In an essay published online in the journal The Lancet, the researchers identified 202 potentially harmful industrial chemicals that may be contributing to dramatic increases in autism, attention deficit hyperactivity disorder (ADHD), and other brain disorders among children.
Roughly half of the chemicals are in common use, but very few have been tested to determine their impact on brain development.
"The bottom line is you only get one chance to develop a brain," Philippe Grandjean, M.D., of the Harvard School of Public Health, tells WebMD. "We have to protect children against chemical pollution because damage to a developing brain is irreversible."
Tip of the Iceberg
Grandjean and co-author Philip Landrigan, M.D., of New York's Mount Sinai School of Medicine, noted that of the industrial chemicals known to be toxic to the human brain, only five — lead, mercury, arsenic, PCBs, and toluene — have been proven to cause damage to the developing brain.
These chemicals have been identified not because they are necessarily more dangerous than the others, but because they have been studied the most, Grandjean and Landrigan contend.
"The few substances proven to be toxic to human neurodevelopment should be viewed as the tip of a very large iceberg," they wrote.
Grandjean spent decades documenting the toxic effects of mercury exposure on the developing brain, and Landrigan spent decades studying the effects of lead exposure in children.
Lead and mercury are among the few chemicals that are now strictly regulated to protect children. But regulation came long after the dangers were first recognized.
Lead-based paint was first linked to sickness in children more than a century ago, but lead was not removed from paint and gasoline in the U.S. until the late 1970s and early 1980s.
"Despite those early pediatric warnings, the largely unchecked use of lead in petrol, paints, ceramic glazes, and many other products through much of the twentieth century caused continued risk of lead poisoning," the researchers write.
A Generation Exposed
Almost all children born in industrialized countries between 1960 and 1980 were exposed to substantial amounts of lead from gasoline. The researchers write that lead exposure in this population could be responsible for a substantial reduction in average IQ scores.
"A generation of American children was exposed to this very dangerous neurotoxin while we were doing traditional risk assessment," Grandjean tells WebMD. "We can't afford to make the same mistake again."
Annette Kirshner, Ph.D., of the National Institute of Environmental Health Sciences (NIEHS) agrees that more expeditious ways of identifying chemical exposures that put children at risk are needed.
The prevailing thinking among researchers studying autism and ADHD is that both genetic and environmental factors play a role in the childhood brain disorders.
"There is still no good evidence linking any single environmental exposure to autism and ADHD," Kirshner tells WebMD. "It will probably require a global effort to understand the combination of factors that lead to these disorders."
But Grandjean and Landrigan argue that exposure to industrial chemicals appear to have created a "silent pandemic in modern society."
"Although these chemicals might have caused impaired brain development in millions of children worldwide, the profound effects of such a pandemic are not apparent from available health statistics," they wrote.
SOURCES: Grandjean, P. and Landrigan, P.J. The Lancet, Nov. 8, 2006; Vol. 368: online edition. Philippe Grandjean, M.D., department of environmental health, Harvard School of Public Health, Boston; Annette Kirshner, Ph.D., health science administrator, National Institute of Environmental Health Sciences.
By Salynn Boyles
Reviewed by Louise Chang
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I saw a program about a school for so called ADHD kids where they had a trampolin in the corner of the room, and whenever a kid started acting out because he couldn't sit still and quiet too long, they would send him to jump on the trampolin for a bit, expend some energy, then come back. Worked great, no drugs required.
SUGAR...which is natural, causes death and disease in the millions every year...diabetes, heart disease etc. your learned and eminent and responsible folks need to research your facts a little better...and don't use the crackpot science that so many use to back up your claims.
Our FDA, just like any other agency, is not 100% perfect. Historically though, US food supply has been the safest in the history of this planet. While companies like BP (British Petroleum) continue to pollute the world with petro-chemical contamination, as the article is talking about when it speaks of the neurotoxin LEAD in gasoline.
The psuedo science that fuels the fears of the ignorant about substance like aspartame and other food additives causes the unnecessary attention and waste of energy on fighting causes of no real worth. These people should be investigating the petro-chemical industry...you will find much to complain about there.
ASPARTAME. The eminent and learned folks responsible for this report have missed a very important factor by excluding meaningful and honest research into this product. We have a saying in England appertaining to dubious substances, "If In Doubt, Kick It Out" and there are certainly a major doubts over this product.
How many more suffering children will it take before your FDA places a total ban on this evil sweet poison. Maybe you are afraid of the litigation which will result.
David Roberts UK