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#776 - Origins of Dementia, Part 1, 20-Aug-2003

(published September 29, 2003)

by Sandra Steingraber, Ph.D.*

Here is a sign of our times: within the publishing world, a new
nonfiction subgenre has emerged -- the Alzheimer's memoir.
Among the first was Elegy for Iris, written by English literary
critic John Bayley about his wife, the novelist Iris Murdoch.
In both the book and the movie based on it, we see the famously
brilliant Murdoch descend into a mental state in which, no
longer able to dress or speak, she desires only to watch the
famously simple children's show, Teletubbies. More recent are
The House on Beartown Road: A Memoir of Learning and Forgetting
by journalist Elizabeth Cohen, which was excerpted in People
magazine, and The Story of My Father by best-selling novelist
Sue Miller, which was profiled in Reader's Digest.[1]

And these include only the books in which the subject of the
story is a former college professor. There are many, many
others.

My own father is a former college professor, and he suffers
from dementia. He now lives in a nursing home. This is hardly
an unconventional situation -- half of all nursing home
residents in the United States are demented[2] -- but the
decision to place him there was an extraordinary one for our
family. After fifty years of marriage, my father wanted to live
out his days with my mother in the house that he had built for
them both when she was a young bride; my mother was devoted to
caring for him there, no matter what it took. And for several
years after his diagnosis she did.

But then Dad became "delusional and combative," in the language
of neurology. "Delusional" meant he came to believe my mother
was having an affair. He grew suspicious when the phone rang.
He followed her to the mailbox, shouting accusations. He
prowled the house at night looking for the other man. He stood
over her while she slept. "Combative" meant that he began to
relive his experiences in Italy during World War II. It was a
dangerous combination.

And so, my retired college professor father -- the man who
introduced me to calculus and Rachel Carson, who planted an
organic garden every spring, who took up the piano in his 40s,
who loved to embroider, bake bread, and make candles, who had
seat belts installed in the family car before they were
standard-issue -- is now institutionalized in a facility from
which he regularly attempts to escape and whose staff he
periodically attempts to assault. He has quite literally become
an imprisoned combatant, which was his biggest fear when, sixty
years ago as a teenage soldier, he sailed into the
Mediterranean on a warship.

In the Alzheimer's wing of the nursing home where he lives a
detailed description of each resident is posted on the door to
their room. It's a way of helping the patients remember where
their beds are located. These biographies also remind my
mother, my sister, and me that Dad is part of a much bigger
tribe. The dementia-sufferers there include former teachers,
former farmers, former entrepreneurs, former church ministers,
former world travelers, former ballroom dancers. Each has a
life history, a family, an identity.

And this small, rural nursing home is itself part of a larger
collective story. In the United States, about 4.5 million
people suffer from Alzheimer's disease, and another 1.5 million
from other forms of dementia. Because the risk of developing a
dementing illness rises sharply with age (ten percent of those
over 65 years old are afflicted with Alzheimer's, while 40
percent of those over 85 are) and because the population itself
is aging rapidly (the first baby boomers turn 65 in 2011), we
are standing on the cusp of a slow-motion epidemic.[3,4] A
disease for which there is no cure, Alzheimer's has already
risen from the 12th leading cause of death to the 8th.[5] By
the year 2050, 10-15 million Americans are projected to have
Alzheimer's -- more than double the number we have now.[3,4]

The economic implications of these statistics are equally
sobering. (And, as an accounting professor, my father would
have found them compelling.) Alzheimer's patients live, on
average, eight years after diagnosis. During this time, they
require, on average, $213,000 in medical care. This makes
Alzheimer's the third most expensive disease in the United
States. (Cancer and heart disease still take the top two
slots.)[3] Yes, someone has done the math: the current economic
burden of Alzheimer's, in medical treatment costs alone, is
about $100 billion each year.[3] One researcher has estimated
that annual costs could rise to $700 billion by 2050.[4] These
figures do not include the one-third of neurodegenerative
dementias that are non-Alzheimer's in origin. The prevalence of
Lewy-body dementia (which is the second most common form of
dementia) and Parkinson's disease (which leads to dementia in
one third of all cases) is also expected to increase sharply as
the population ages.[6,7]

All these diseases are officially classified as "idiopathic
disorders of unknown pathogenesis,"[7] which is another way of
saying that no one knows what causes them. Thus, in addition to
presenting overwhelming personal challenges to those afflicted
and to their caregivers, neurodegenerative dementia brings with
it four other miserable characteristics: it has no known cause;
it has no known cure; it is becoming increasingly common; and
it costs considerably more than an average home mortgage to
care for each person diagnosed.

Clearly, then, addressing the question of dementia's causality
should be a national priority. Some medical researchers are
indeed working feverishly to understand the genesis of
dementia, and, while their efforts have not yet taken on the
coordinated urgency that has characterized, say, the atomic
bomb program in the 1940s or the space program in the 1960s,
there are signs of an emerging new framework for inquiry.

In May 2003, the Mount Sinai School Center for Children's
Health and the Environment organized an important conference at
the New York Academy of Medicine entitled "Early Environmental
Origins of Neurodegenerative Disease in Later Life."[8] In
Rachel's #777, we will take a close look at the evidence for an
environmental connection to Alzheimer's and Parkinson's
disease. Here we will examine the conceptual rationale for
pursuing early-life environmental links to late-life dementias,
as presented at this ground-breaking conference.

The chain of logic goes as follows. First, inheritance alone
appears to play little direct role in the risk of developing
dementia. (Heredity explains only five percent of Parkinson's
disease, for example.[9]) This means we need to look toward the
environment, possibly in concert with genetics and lifestyle
factors, to understand dementia's root causes.

Second, many neurodegenerative diseases are thought to arise
through a series of stages that require many years or even many
decades to progress. The cascade of neuronal changes leading to
Alzheimer's may already be evident in one's 20s or 30s.[10]
This means toxic exposures early in life -- even prenatal
exposures -- may be more relevant to late-life dementias than
equivalent exposures encountered later.[5]

Third, many cognitive disorders known to be caused by exposure
to toxic chemicals have decades-long latent effects. Dupont
workers exposed to high levels of lead on the job showed more
rapid cognitive declines during their retirements than
coworkers exposed to lower lead levels, even though neither
group had been exposed to any lead for almost twenty years.
Similar findings come from South Korea.[11]

Fourth, animal studies show that early-life exposures to
certain neurotoxic chemicals can create subtle but permanent
changes in the brain that produce no functional deficits until
the effects of these "silent toxicities" are unmasked by later
challenges.[12] This means early-life exposures to neurotoxic
chemicals can enhance susceptibility to late-life exposures.

Fifth, neurotoxic chemicals, in the form of pesticides,
persistent organochlorines, and heavy metals, are widely
distributed in the U.S. environment.[5]

Sixth, human studies of non-dementing illnesses show that
certain factors encountered early in life can predispose an
individual to the development of disease in their elder years.
For example, studies in England show that babies born small
because they were denied adequate nutrition in the womb develop
into adults who are, in advanced age, at higher risk of
hypertension, stroke, diabetes, and breast or prostate cancer.
The results of these studies suggest that infants are
"programmed" by environmental insults that take place at a
critical period of development in ways that have lifelong
consequences. This idea is known as the Barker Hypothesis.[13]
In Rachel's #777, we shall explore the relevance of the Barker
Hypothesis for Alzheimer's and Parkinson's Disease.
==============

*Sandra Steingraber is a biologist and author (see Rachel's
#565). She is currently a Distinguished Visiting Scholar in the
Interdisciplinary Studies Program at Ithaca College in Ithaca,
New York.

Unless otherwise noted, all citations refer to presentations
made at the Mt. Sinai School of Medicine conference, "Early
Environmental Origins of Neurodegenerative Disease in Later
Life: Research and Risk Assessment" (New York Academy of
Medicine, May 16, 2003). Conference proceedings are currently
in preparation for publication.

[1] J. Bayley, Elegy for Iris (New York: St. Martins Press,
1999); E. Cohen, The House on Beartown Road: A Memoir of
Learning and Forgetting (New York: Random House, 2003); S.
Miller, Story of My Father (New York: Knopf, 2003).

[2] Robert Butler, M.D., President and CEO, International
Longevity Center, "Early Determinants of Disease in the
Elderly."

[3] M. Saleem Ismail, "Trials, Tribulations and Triumphs in
Alzheimer's Disease: Where Are We Now and Where Are We Going?"
presentation at the Ithaca College Gerontology Institute
conference, "Meeting the Challenge of Dementia," May 29, 2003.

[4] D. Shenk, The Forgetting -- Alzheimer's: Portrait of an
Epidemic (New York: Doubleday, 2001), pg. 5.

[5] Introduction to conference proceedings, pgs. 1-2.

[6] G.B. Wilks, "Supportive Treatment of Lewy Body Dementia,"
Patient Care Vol. 34 (2002), pgs. 85-90.

[7] R.L Nussbaum and C.E. Ellis, "Alzheimer's Disease and
Parkinson's Disease," New England Journal of Medicine Vol. 348
(2003), pgs. 1356-64.

[8] Co-organizers of the conference were the International
Longevity Center, the Bachmann-Strauss Dystonia and Parkinson
Foundation, and the Children's Environmental Health Network.

[9] C. Warren Olanow, M.D., Mt. Sinai School of Medicine, "New
Research in Parkinson's Disease."

[10] John Morrison, Ph.D., Mt. Sinai School of Medicine,
"Neurobiology of Aging and Dementia,"

[11] Andrew Todd, Ph.D., Mt. Sinai School of Medicine, "Lead
and Loss of Cognition."

[12] Deborah Cory-Slechta, Ph.D., University of Rochester,
"Animal Models of Parkinson's Disease."

[13] C. Osmond and D.J.P. Barker, "Fetal, Infant, and Childhood
Growth Are Predictors of Coronary Heart Disease, Diabetes, and
Hypertension in Adult Men and Women," Environmental Health
Perspectives Vol. 108 Supplement 3 (2000), pgs. 545-553.