I think that there is a huge problem out there that the silent latency is masking as it did with other medical / environmental / poisoning diagnostic disasters.

Cheers

Doug Humphries 

--- In LPAE@yahoogroups.com, <egroup@...> wrote:
>
> for all those interested in later health effects of lead (and pesticides and
> mercury, etc) please refer to the website below. I have also pasted the text
> of the article at the end.
> Kind regards
> Elizabeth O'Brien
>
> ----- Original Message -----
> From: "Ralph Scott" rscott@...
> To: leadnet@...
> Sent: Wednesday, June 18, 2008 6:12 AM
> Subject: [Leadnet] "Is lead linked to mental decline?"
>
>
> A June 15 news story that reviews some research on lead exposure in
> childhood and mental decline later in life:
>
> www.orlandosentinel.com/orl-leadbrain08jun15,0,3574316.story
> ----------
> Ralph Scott
> Community Projects Director
> Alliance for Healthy Homes
> 50 F St., NW, Suite 300
> Washington, DC 20001
>
> phone - 202-347-7610
> fax - 202-347-0058
> rscott@...; www.afhh.org
>
> Working for affordable healthy housing for all.
>
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> www.orlandosentinel.com/orl-leadbrain08jun15,0,3574316.story
> [LID 9565]
>
> OrlandoSentinel.com
> YOUR TIME: WELLNESS
> Is lead linked to mental decline?
> Some experts say long-ago exposure to the toxin adversely affects the brain
> later in life, but more study is necessary.
> Malcolm Ritter
>
> The Associated Press June 15, 2008
>
> Could it be that the "natural" mental decline that afflicts many older
> people is related to how much lead they absorbed decades before?
>
> That's the provocative idea emerging from some studies, part of a broader
> area of new research that suggests some pollutants can cause harm that shows
> up only years after someone is exposed.
>
> The work suggests long-ago lead exposure can make an aging person's brain
> work as if it's five years older than it really is. If that's verified by
> more research, it means that sharp cuts in environmental lead levels more
> than 20 years ago didn't stop its widespread effects.
>
> "We're trying to offer a caution that a portion of what has been called
> normal aging might in fact be due to ubiquitous environmental exposures like
> lead," says Dr. Brian Schwartz of Johns Hopkins University.
>
> "The fact that it's happening with lead is the first proof of principle that
> it's possible," says Schwartz, a leader in the study of lead's delayed
> effects. Other pollutants such as mercury and pesticides may do the same
> thing, he says.
>
> In fact, some recent research does suggest that being exposed to pesticides
> raises the risk of getting Parkinson's disease a decade or more later.
> Experts say such studies in mercury are lacking.
>
> The notion of long-delayed effects is familiar; tobacco and asbestos, for
> example, can lead to cancer. But in recent years, scientists are coming to
> appreciate that exposure to other pollutants in early life also may promote
> disease much later on.
>
> "It's an emerging area" for research, says Dr. Philip Landrigan of the Mount
> Sinai School of Medicine in New York. It certainly makes sense that if a
> substance destroys brain cells in early life, the brain may cope by drawing
> on its reserve capacity until it loses still more cells with aging, he said.
> Only then would symptoms such as forgetfulness or tremors appear.
>
> Linda Birnbaum, director of experimental toxicology at the U.S.
> Environmental Protection Agency, says infant mice exposed to chemicals such
> as PCBs show only very subtle effects in young adulthood. But more dramatic
> harm in areas such as movement and learning appears when they reach old age.
>
> Animal studies also show clear evidence that being exposed to harmful
> substances in the womb can harm health later on, she says. For example,
> rodents that encounter PCBs or dioxins before birth are more susceptible to
> cancer once they grow up.
>
> Studying delayed effects in people is difficult because they generally must
> be followed for a long time. Research with lead is easier because scientists
> can measure the amount that has accumulated in the shinbone over decades and
> get a read on how much lead a person has been exposed to in the past.
>
> Lead in the blood, by contrast, reflects recent exposure. Virtually all
> Americans have lead in their blood, but the amounts are far lower today than
> in the past.
>
> The big reason for the drop: the phasing out of lead in gasoline from 1976
> to 1991. Because of that and accompanying measures, the average lead level
> in the blood of American adults fell 30 percent by 1980 and about 80 percent
> by 1990.
>
> That's a major success story for environmentalists. But work by Schwartz and
> Dr. Howard Hu of the University of Michigan suggests that the long-term
> effects of the high-lead era are still being felt.
>
> In 2006, Schwartz and his colleagues published a study of about 1,000
> Baltimore residents. They were ages 50 to 70, old enough to have absorbed
> plenty of lead before it disappeared from gasoline. They probably got their
> peak doses in the 1960s and 1970s, Schwartz says, mostly by inhaling air
> pollution from vehicle exhaust and from other sources in the environment.
>
> The researchers estimated each person's lifetime dose by scanning their
> shinbones for lead. Then they gave each one a battery of mental-ability
> tests.
>
> In brief, the scientists found that the higher the lifetime lead dose, the
> poorer the performance across a wide variety of mental functions, such as
> verbal and visual memory and language ability. From low to high dose, the
> difference in mental functioning was about the equivalent of aging by two to
> six years.
>
> "We think that's a large effect," Schwartz says.
>
> Hu and his colleagues took a slightly different approach in a 2004 study of
> 466 men with an average age of 67. Those men took a mental-ability test
> twice, about four years apart on average. Those with the highest bone lead
> levels showed more decline between exams than those with smaller levels,
> with the effect of the lead equal to about five years of aging.
>
> Nobody is claiming that lead is the sole cause of age-related mental
> decline, but it appears to be one of several factors involved, Hu stresses.
>
> If so, it would join such possible influences as high blood pressure,
> diabetes, stroke, emotional stress and maybe education level, said Bradley
> Wise of the National Institute on Aging. Nobody knows exactly what causes
> mental decline with age, he says.
>
> Although the studies by Hu and Schwartz suggest lead is involved, Wise and
> others say they don't prove the link.
>
> "I think many things impact how we age, but I think right now it's maybe
> premature to be giving lead a huge role in our age-related cognitive
> decline," says Dr. Margit L. Bleecker, director of the Center for
> Occupational and Environmental Neurology in Baltimore. Still, she calls the
> lead hypothesis "a very interesting idea" deserving more study.
>
> Others are more impressed.
>
> "The new evidence from these studies should concern people" says
> epidemiologist Andrew Rowland of the University of New Mexico. "These two
> research groups are finding adverse effects on the aging brain at low levels
> of lead exposure. More work needs to be done, but these studies are raising
> important questions."
>
>
>
>
> Copyright © 2008, Orlando Sentinel
>