(July 2001)

Alzheimer’s is a devastating disease that first robs people of their memory and eventually, in most cases, of their personalities and their mental functioning, reducing them to bodies with destroyed brains. It is a personal and family disaster that affects millions of older people in the United States. Its cause is not yet known. A presentation by investigators from Case Western University Medical School in Ohio at the American Academy of Neurology meeting in May 2000 indicated that workers exposed to lead (including lead smelters and manufacturing of lead-containing batteries, pottery, pipes, and ammunition) had a more than doubled risk of Alzheimer’s.

Because this was an oral presentation, further review will be needed to determine whether the patients had true Alzheimer’s or another form of dementia. But, in either case, the study is interesting and important. We are accustomed to thinking of lead poisoning as a childhood disease. In past decades when children were more heavily exposed to environmental lead, the symptoms of lead-induced brain damage were dramatic, including convulsions and, in later stages, coma. As leaded gasoline and indoor lead-based paints have been phased out, the focus has shifted to subtle lead intoxication at much lower blood lead concentrations. That form of lead poisoning, affecting millions of American children, is characterized by lowered IQs, lessened school success, increased school drop-out rates, reduced attention spans, and anti-social, even aggressive, behaviors.

But, lead poisoning is not just a childhood problem. Once lead is absorbed into the body from the intestinal tract or by inhaling it (or even through the skin), it settles in the bones and stays there throughout adult life. Indeed, bone lead stores increase with aging. Lead has been implicated as contributing to some cases of high blood pressure and some cases of adult kidney failure.

A huge and unanswered question has been whether enough lead that is stored in bones could, as the body ages and physiology changes, get out of the bones, and cause trouble in other tissues, especially the brain. This study says that more heavily exposed adults, whose bone lead levels would be higher than found in less exposed adults, had a modestly increased risk of developing incapacitating dementia, presumably because the lead got out of the bones and into their brains.

It should be made very clear that this is still an unpublished oral presentation and is a preliminary study. It will require confirmation by other studies. Furthermore, it does not suggest that lead is the cause of or even a major contributor to most cases of Alzheimer’s. Only eight percent of the 185 Alzheimer’s disease patients had a greater lead exposure than found in 303 controls.

Nevertheless, it is an intriguing report that brings up another question that has interested Healthful Life for a long time. Is it possible that some of the "normal" memory loss that, for many, accompanies the aging process may be due, in some people, to the lead that all of us (including those not particularly exposed to lead in the work place) have in our bones moving to the brain from those bone storage sites.

That is pure speculation, but this report on lead and dementia in older persons gives emphasis to the importance of that question and strongly suggests that proper studies should be done to determine whether that speculation might be true.

Cleaning up environmental lead (particularly in old houses where lead-based paints were used) will help, but it cannot solve the problem. Increasing calcium intake is the only true preventive action that is likely to be effective.

Lower body lead burdens in children means less lead in the bones of older people that can get from bones to other tissues, including the brain.

Healthful Life believes the "get calcium in, keep lead out" campaign that has been started in New Jersey should become national policy if the evaluation built into the campaign does, indeed, show, as the experimental and human evidence strngly suggest, that increasing calcium intake does lower body lead burdens.