Alzheimer's, Dementia & Mental Health
Senior’s Nightmare: No Prevention, No Cure for
Alzheimer’s Disease Says Expert NIH Panel
‘Alzheimer's disease is a feared and heart-breaking
disease - wish we could tell people that taking a pill or doing a puzzle
every day would prevent this terrible disease, but current evidence
doesn't support this’
April 28, 2010 - Many preventive measures for
cognitive decline and for preventing Alzheimer's disease—mental
stimulation, exercise, and a variety of dietary supplements—have been
studied over the years. However, an independent panel convened this week
by the National Institutes of Health determined that the value of these
strategies for delaying the onset and/or reducing the severity of
decline or disease hasn't been demonstrated in rigorous studies.
"Alzheimer's disease is a feared and heart-breaking
disease," said Dr. Martha L. Daviglus, conference panel chair and
professor of preventive medicine and medicine at Northwestern
University, Chicago. "We wish we could tell people that taking a pill or
doing a puzzle every day would prevent this terrible disease, but
current evidence doesn't support this."
The panel's assessment of the available evidence
revealed that progress to understand how the onset of these conditions
might be delayed or prevented is limited by inconsistent definitions of
what constitutes Alzheimer's disease and cognitive decline.
Other
factors include incomplete understanding of the natural history of the
disease and limited understanding of the aging process in general. The
panel recommended that the research community and clinicians collaborate
to develop, test, and uniformly adopt objective measures of baseline
cognitive function and changes over time.
Although many non-modifiable risk factors have been
examined, age is the strongest known risk factor for Alzheimer's
disease. Additionally, a genetic variant of a cholesterol-ferrying
protein (apolipoprotein E), has strong evidence of association with the
risk for developing Alzheimer's disease. Although it is hoped that
improved understanding of genetic risk factors may ultimately lead to
effective therapies, currently these associations are primarily useful
in the clinical research setting.
The panel determined that there is currently no
evidence of even moderate scientific quality supporting the association
of any modifiable factor—dietary supplement intake, use of prescription
or non-prescription drugs, diet, exercise, and social engagement—with
reduced risk of Alzheimer's disease. The evidence surrounding risk
reduction for cognitive decline is similarly limited. Low-grade evidence
shows weak associations between many lifestyle choices and reduced risk
of Alzheimer's disease and cognitive decline.
Although there is little evidence that these
interventions lessen cognitive decline, some are not necessarily harmful
and may confer other benefits. However, the panel also emphasized the
need for enhanced public understanding that these proposed prevention
strategies are currently, at best, only loosely associated with improved
outcomes. This means that carefully-designed randomized studies may
reveal that these modifiable factors enhance, detract, or have no effect
on preventing Alzheimer's disease and cognitive decline.
"These associations are examples of the classic
chicken or the egg quandary. Are people able to stay mentally sharp over
time because they are physically active and socially engaged or are they
simply more likely to stay physically active and socially engaged
because they are mentally sharp?" added Dr. Daviglus. "An association
only tells us that these things are related, not that one causes the
other."
The panel found that certain chronic diseases, such
as diabetes and depression, and risk factors such as smoking are
associated with increased risk of both Alzheimer's disease and cognitive
decline. However, studies have not yet demonstrated that these medical
or lifestyle factors actually cause or prevent Alzheimer's disease or
cognitive decline, only that they are related.
There is insufficient evidence to support the use
of pharmaceuticals or dietary supplements to prevent Alzheimer's disease
or cognitive decline. Ongoing studies exploring factors including but
not limited to physical activity, omega-3 fatty acids (typically found
in fish), antihypertensive medications, and cognitive engagement may
provide new insight into Alzheimer's disease and cognitive decline
prevention.
The panel made a variety of recommendations to
shape the future research agenda and fill identified gaps, while
acknowledging that advancing our understanding of these complex
conditions in order to develop conclusive, evidence-based prevention
recommendations will require considerable time and resources. For
example, the panel advocated launching long-term, longitudinal studies
to better characterize the natural history and progression of these
diseases in the community. They also recommended the establishment of
registries for Alzheimer's disease and cognitive decline, modeled on
existing registries for cancer.
Extensive research over the past 20 years has
provided important insights on the nature of Alzheimer's disease and
cognitive decline and the magnitude of the problem. Nevertheless, there
remain important and formidable challenges in conducting research on
these diseases, particularly in the area of prevention. There are
numerous ongoing or planned investigations which may offer promising new
insights regarding the causes and prevention of these diseases.
An updated version of the panel's draft consensus
statement, which incorporates comments received during this morning's
public session, will be posted later today at
http://consensus.nih.gov.
The panel will hold a press telebriefing to discuss
their findings today at 2:00 p.m. EDT. To participate, call
1-888-428-7458 (US) or 201-604-1577 (International) and reference the
NIH Alzheimer's conference. Audio playback will be available shortly
after conclusion of the telebriefing, by calling 1-888-632-8973 (U.S.)
or 201-499-0429 (International) and entering replay code 35986458.
The conference was sponsored by the NIH Office of
Medical Applications of Research and the National Institute on Aging,
along with other NIH and Department of Health and Human Services
components. This conference was conducted under the NIH Consensus
Development Program, which convenes conferences to assess the available
scientific evidence and develop objective statements on controversial
medical issues.
The 15-member panel included experts in the fields
of preventive medicine, geriatrics, internal medicine, neurology,
neurological surgery, psychiatry, mental health, human nutrition,
pharmacology, genetic medicine, nursing, health economics, health
services research, and family caregiving. A complete listing of the
panel members and their institutional affiliations is included in the
draft conference statement. Additional materials, including panel bios,
photos, and other related resources, are available at
http://consensus.nih.gov/2010/alzmedia.htm. Interviews with panel
members can be arranged by contacting Lisa Ahramjian at 301-496-4999 or
AhramjianL@od.nih.gov.
The conference was webcast live and will be
archived shortly. Links to the archived webcast will be available at
http://consensus.nih.gov/2010/alz.htm.
Individuals interested in obtaining resources for
patients and families affected by Alzheimer's disease may wish to
contact the National Institute on Aging's Alzheimer's Disease Education
and Referral Center at 1-800-438-4380 or
http://www.nia.nih.gov/alzheimers.
In addition to the material presented at the
conference by speakers and the comments of conference participants
presented during discussion periods, the panel considered pertinent
research from the published literature and the results of a systematic
review of the literature. The systematic review was prepared through the
Agency for Healthcare Research and Quality Evidence-based Practice
Centers (EPC) program, by the Duke University Evidence-based Practice
Center. The EPCs develop evidence reports and technology assessments
based on rigorous, comprehensive syntheses and analyses of the
scientific literature, emphasizing explicit and detailed documentation
of methods, rationale, and assumptions. The evidence report on
preventing Alzheimer's disease and cognitive decline is available at
http://www.ahrq.gov/clinic/tp/alzcogtp.htm.
The panel's statement is an independent report and
is not a policy statement of the NIH or the federal government. The NIH
Consensus Development Program was established in 1977 as a mechanism to
judge controversial topics in medicine and public health in an unbiased,
impartial manner. NIH has conducted 122 consensus development
conferences, and 34 state-of-the-science (formerly "technology
assessment") conferences, addressing a wide range of issues. A
backgrounder on the NIH Consensus Development Program process is
available at
http://consensus.nih.gov/backgrounder.htm.
The Office of the Director, the central office at
NIH, is responsible for setting policy for NIH, which includes 27
Institutes and Centers. This involves planning, managing, and
coordinating the programs and activities of all NIH components. The
Office of the Director also includes program offices which are
responsible for stimulating specific areas of research throughout NIH.
Additional information is available at
http://www.nih.gov/icd/od.
The National Institutes of Health (NIH) —
The Nation's Medical Research Agency
— includes 27 Institutes and Centers and is a component of the U.S.
Department of Health and Human Services. It is the primary federal
agency for conducting and supporting basic, clinical and translational
medical research, and it investigates the causes, treatments, and cures
for both common and rare diseases. For more information about NIH and
its programs, visit
www.nih.gov.
