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Vol. LXII, No. 11
May 28, 2010
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No Evidence of Magic Bullet
Nothing Proven to Ward Off Alzheimer’s, Panel Says

On the front page...

It wasn’t the news anyone wanted to hear: Currently, there’s no conclusive evidence that taking any substance or engaging in any activity can prevent or delay Alzheimer’s disease or cognitive decline, according to an independent panel convened by the NIH Office of Medical Applications of Research. The panel, however, also concluded that interventions such as exercise or diabetes control—already known to benefit healthy aging—might be a productive line of study.

The state-of-the-science group announced its findings Apr. 28, after hearing 2 full days of medical experts discuss both Alzheimer’s and age-related cognitive decline.

“It is tragic that just as we have succeeded in extending lifespan and decreasing disability due to so many other causes that we now face an increasing urgency in addressing the problems of Alzheimer’s disease and age-related cognitive decline, changes that rob older men and women of the ability to fully enjoy life in its later years,” said National Institute on Aging director Dr. Richard Hodes, who opened the conference Apr. 26 in a packed Natcher auditorium. NIA was a primary sponsor of the conference with OMAR.

Continued...


  Panel chair Dr. Martha Daviglus delivers the conference state-of-the-science statement.  
  Panel chair Dr. Martha Daviglus delivers the conference state-of-the-science statement.  

Plaques and Tangles

First described in 1906 by German psychiatrist-neuropathologist Alois Alzheimer, the disease named after that physician is the most common form of dementia. Alzheimer wrote of a 51-year-old female patient who showed signs of memory loss, language problems and unpredictable behavior. After she died, he studied photomicrographs of her brain and found what became the hallmarks of the disease: abnormal clumps of protein identified as “beta-amyloid plaques” and disorderly bundles of protein called “neurofibrillary tangles.”

Over the course of a lifetime, most people remain cognitively stable, experiencing only limited declines in short-term memory and processing speed. But for some, the loss in memory and cognitive function is more severe and, ultimately, interferes significantly with daily life. That’s when the possibility of Alzheimer’s or another form of dementia must be considered.

Panelists Dr. Wade Berrettini (l) and Dr. Carl Bell. Panelists Dr. Kathleen McGarry (l) and Gail Hunt. Dr. Mary Ganguli of Western Psychiatric Institute and Clinic, University of Pittsburgh Medical Center, gives an overview of Alzheimer’s disease.

Above, l:
Panelists Dr. Wade Berrettini (l) and Dr. Carl Bell.

Above, c:
Panelists Dr. Kathleen McGarry (l) and Gail Hunt.

Above, r:
Dr. Mary Ganguli of Western Psychiatric Institute and Clinic, University of Pittsburgh Medical Center, gives an overview of Alzheimer’s disease.

What complicates diagnosis, according to several conference presenters, is that physicians at the primary care level may not have enough time or sensitive enough tools to determine the nature of a patient’s memory loss. For example, what differentiates normal, age-related cognitive decline from mild cognitive impairment or from the earliest stages of Alzheimer’s disease?

What used to be a rarely reported disease, the panel noted in its introduction, Alzheimer’s now has become “one of the most common disabling disorders among older individuals.” Alzheimer’s accounts for 60 percent to 80 percent of all dementia diagnoses, depending on the criteria used. Estimates vary, but experts report between 2.6 million and 5.1 million Americans may have the disorder. That number is expected to grow as Baby Boomers age.

What the Panel Found

The 15-member panel included experts in a number of relevant fields such as geriatrics, neurology, preventive medicine, psychiatry, human nutrition, pharmacology and nursing. Specifically selected not to be experts in Alzheimer’s disease and cognitive decline, and therefore without preconceptions of the conference questions, the panel drew several conclusions:

  • 20 years of extensive research has provided substantial information on the nature of Alzheimer’s disease and cognitive decline. While critical knowledge gaps still remain, particularly in the areas of causes and prevention, a number of observational studies and a few short-term clinical trials offer new insights.
  • Currently, outside of a neurologist’s office or research setting, there are no “highly reliable consensus-based diagnostic criteria for cognitive decline, mild cognitive impairment and Alzheimer’s,” and available criteria at the clinician level are not “uniformly applied.”
  • Alzheimer’s and related ailments are major sources of disability and death worldwide that significantly burden not only those who have the diseases, but also their caregivers and society in general.
  • The medical community does not have enough evidence to support using any drug, dietary supplement or behavioral change to prevent Alzheimer’s or cognitive decline. Results from ongoing studies in some of these areas, including studies of antihypertensive medications and physical activity, could possibly shed more light on warding off the disorders. However, it is too soon to conclude that any intervention is effective in preventing Alzheimer’s or cognitive decline, the panel noted repeatedly.
  • Large-scale population-based studies and randomized controlled trials—the gold standard evidence in medical research—will be needed to look into strategies that may help maintain cognitive function in people at risk for decline and find ways to delay onset and slow progression of Alzheimer’s disease.

Facts, Not Fiction

One of close to two dozen expert presenters at the recent conference on cognitive decline, Dr. Ronald Petersen of the Alzheimer’s Disease Research Center at Mayo Clinic College of Medicine, discusses early diagnosis of the disorder.

One of close to two dozen expert presenters at the recent conference on cognitive decline, Dr. Ronald Petersen of the Alzheimer’s Disease Research Center at Mayo Clinic College of Medicine, discusses early diagnosis of the disorder.

At a public reading of the panel’s draft statement on day 3, several audience members expressed dismay that the conclusions were overly negative and pessimistic. During an afternoon media teleconference, several panel members addressed these concerns and sympathized with the public’s frustration, emphasizing the importance of basing their findings on scientific evidence.

“Physicians can actually benefit from the information contained in this report,” said panelist Dr. Evelyn Granieri of Columbia University. “It provides them with factual information.”

Another panelist, Dr. Carl Bell of the University of Illinois at Chicago, said, “From a personal perspective, being 63, I’m scared to death of this disorder and I know that a lot of my Baby Boomer colleagues are also terrified.”

Such fears, the panel acknowledged, can cause people to spend money on herbal treatments and other interventions that have not been proven. That’s exactly where panel members hope this report can help.

“Since we don’t have any solid evidence that there is anything to prevent either cognitive decline or dementia, we hope physicians will discuss this report with their patients and…dissuade folks who have this and their caregivers from spending extraordinary amounts of money on stuff that doesn’t work,” Bell concluded.

In the meantime, there is something people can do to help fight Alzheimer’s, another panelist pointed out.

“One of the most important things doctors and people who start to recognize problems can do is to get engaged in the research community,” said Dr. Arnold Potosky of Georgetown University. “There’s a vital need for more research. Our conclusions were heavy on recommendations to do more to track these diseases over the long term, to learn more about their causes and progression.” NIHRecord Icon

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