Alzheimer's Association Update September 2010

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• AAICAD draws Alzheimer's researchers from around the globe

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AAICAD draws Alzheimer's researchers from around the globe 

Nearly 4,000 researchers from 60 countries gathered in Honolulu, Hawaii, July 10–15 to learn the latest in Alzheimer research at the Alzheimer's Association International Conference on Alzheimer's Disease (AAICAD) 2010. The world's largest gathering of Alzheimer's disease (AD) researchers included a full day of presentations focused on imaging technologies related to early detection and diagnosis of AD. The Alzheimer's Imaging Consortium drew a record 800 attendees to this burgeoning area of research.

Association President and CEO Harry Johns told attendees, “The field of Alzheimer research is moving on all fronts and in new and different directions. Your attendance at AAICAD speaks to the excitement felt in the science community, and the Association is thrilled to help build upon that excitement by providing a strong program of plenary, symposia, poster and other presentations at AAICAD 2010.

“Through this annual meeting, we aim to foster the information sharing and collaboration among scientists that we know is essential to accelerating progress toward our vision of a world without Alzheimer's.”

Among the more than 2,000 presentations offered at AAICAD were several related to revising the diagnostic criteria for AD. The current criteria were established in 1984. “Important scientific discoveries have been made in Alzheimer's, and there have been significant changes in our knowledge and conception of the disease,” said Creighton H. Phelps, PhD, Director of the Alzheimer's Disease Centers Program, Division of Neuroscience, National Institute on Aging (NIA) at the National Institutes of Health. “The NIA and the Alzheimer's Association, after consultation with the Alzheimer's scientific and medical community, concluded that the diagnostic criteria may need to be revised to incorporate scientific advances. We decided to convene workgroups to examine the literature and make recommendations.”

At AAICAD, leaders of the three workgroups—which covered AD dementia, mild cognitive impairment (MCI) due to AD, and preclinical AD—presented preliminary reports at a special session for initial comment by the AD community. “The proposals would change the 1984 criteria by better reflecting the various stages of the disease and the inclusion of Alzheimer's disease biomarkers,” said William Thies, PhD, Chief Medical and Scientific Officer at the Association. “While the role of biomarkers differs in each of the three proposed stages, much remains to be understood concerning their reliability and validity in diagnosis. This makes it critical that we thoroughly test these new biomarker-related recommendations, which are meant for research settings only at this juncture.” The NIA and Association have launched a Web site, www.alz.org/research/diagnostic_criteria, soliciting input on the new criteria. After that input is incorporated into the criteria, the NIA and Association will seek publication of the criteria in a peer-reviewed journal, followed by validation of the criteria through a variety of research studies.

Also at AAICAD, the Alzheimer's Association TrialMatch™ clinical studies matching service was launched to facilitate recruitment of volunteers for clinical studies. “TrialMatch provides a first-of-its-kind service in Alzheimer's by delivering a user-friendly and individualized guide to clinical trials for people with Alzheimer's, their healthcare professionals, caregivers and healthy volunteers,” said Dr Thies. In addition, TrialMatch enables researchers seeking volunteers to submit information on their studies for potential inclusion by the service. For more information, call 1-800-272-3900, or visit www.alz.org/trialmatch.

In addition, AAICAD marked the debut of a new section of the Association Web site devoted to AD research and science, www.alz.org/research. Among the features of the site, which is geared toward researchers and non-researchers alike, are profiles of leading AD scientists, key dates for the Alzheimer's Association 2011 International Research Grant Program, information on the causes and treatment of AD, discoveries from recent clinical studies, and a description of the clinical studies process.

Results of clinical and other research studies were showcased at AAICAD. Evidence from long-term, large-scale studies presented at the conference suggested an association between physical activity and diet in maintaining cognitive ability and reducing dementia risk in older adults. This evidence includes data from the Framingham Study, a population-based study that began in 1948 to examine cardiovascular disease risk but to which a cognitive assessment component was later added. Of 1,200 elderly participants followed up for up to two decades, 242 developed dementia, including 193 with AD. Individuals who participated in an hour or more of moderate or heavy exercise per day had a 45 percent decreased risk of developing dementia. Moderate exercise included housework, climbing stairs, and light sports such as bowling and golf; heavy exercise included heavy housework and intensive exercise such as jogging. Individuals with the lowest level of exercise had a 45 percent increased risk of dementia.

“This is the first study to follow a large group of individuals for this long a period,” said presenter Zaldy Tan, MD, MPH. “It suggests that lowering the risk for dementia may be one additional benefit of maintaining at least moderate physical activity, even into the eighth decade of life.”

Observational studies have shown associations between consumption of either tea or coffee and cognitive function in older adults, but data including long-term follow-up and rate of change in cognitive function are lacking. Lenore Arab, PhD, and colleagues analyzed data from more than 4,800 Cardiovascular Health Study participants aged 65 and older to examine the relationship between consumption of tea and coffee and change in cognitive function over time. Study participants were followed up for up to 14 years. Researchers found that people who consumed tea had significantly less cognitive decline than non-tea drinkers. More specifically, study participants who drank tea 5–10 times/year, 1–3 times/month, 1–4 times/week, and 5+ times/week had average annual rates of decline 17 percent, 32 percent, 37 percent, and 26 percent lower, respectively, than non-tea drinkers. Coffee consumption did not show any effect except at the very highest level of consumption—where it was associated with a 20 percent decrease in cognitive decline.

Data on AD risk obtained from the National Health and Nutrition Examination Survey showed that among 3,325 individuals aged 65 or older, those with vitamin D deficiency were 42 percent more likely to develop cognitive impairment than individuals without vitamin D deficiency, and those with severe vitamin D deficiency had a 394 percent increased risk, making them nearly four times as likely to develop cognitive impairment as those who were not vitamin D deficient. “It appears that the odds of cognitive impairment increase as vitamin D levels go down, which is consistent with the findings of previous European studies,” said David Llewellyn, PhD. “Given that both vitamin D deficiency and dementia are common throughout the world, this is a major public health concern.”

More than half of older Americans have insufficient levels of vitamin D. Causes include spending too little time in the sun to produce adequate levels of vitamin D, decreased vitamin D production with aging, inadequate dietary sources of vitamin D and vitamin D fortification of foods, decreased vitamin D levels due to obesity, and insufficient use of vitamin D supplements. “Vitamin D supplements have proven to be a safe, inexpensive, and effective way to treat deficiency. More research is urgently needed to establish whether vitamin D supplementation has therapeutic potential for dementia,” Dr Llewellyn said.

Insulin may also have therapeutic potential. Suzanne Craft, PhD, presented data from a four-month clinical trial showing that among 104 individuals with mild cognitive impairment or AD randomized to receive placebo or 20 or 40 IU of insulin daily via intranasal administration, those receiving insulin benefited from the treatment. These benefits included improved or stabilized cognitive and functional abilities, stabilized glucose metabolism in the brain, and an improved ratio of beta-amyloid 40:42 in cerebrospinal fluid. Insulin is used throughout the brain, facilitating neuronal communication, synapse health, and regulation of beta-amyloid levels. Earlier research has shown that people with AD have decreased levels of insulin in the brain and that levels further decrease as the disease progresses. Decreased insulin levels are evident in even the earliest stages of AD (Braak stages 0–1 and 2–3), said Dr Craft. Insulin delivered intranasally bypasses the blood-brain barrier and increases insulin levels in the hippocampus and other areas important to memory. "We believe that restoring normal insulin function in the brain may provide therapeutic benefits to adults with Alzheimer's,” said Dr Craft.

The benefits of early detection of AD were the focus of the Dementia Demonstration Project, which involved more than 8,000 veterans aged 70 and older at seven veterans administration medical centers. While the intention of the demonstration project was to identify individuals with dementia to help ensure that they received information, support, and care coordination, researchers were surprised to learn that early diagnosis also led to significant short-term cost savings. Of 8,000 veterans without a history of AD or other dementia who underwent a brief memory test as part of a primary care visit, 25 percent failed the test. Thirty-four percent of those who failed the test returned for a dementia evaluation, and of these, 95 percent were found to have significant cognitive impairment, including 76 percent with dementia. Health care costs for individuals whose cognitive impairment was diagnosed decreased an average of $2,500 in the year after diagnosis (from more than $14,000 to about $11,500).

Implementing a screening program on a larger scale could translate into billions of dollars saved annually, said J. Riley McCarten, MD, the project's lead physician. Dr McCarten emphasized that the importance of early detection goes beyond saving money. “Dementia, any [form of] cognitive impairment, is a serious health care issue,” he said. “We should be doing everything we can to look for it. We should reward people who find it; [for] people who ignore it, there should be a penalty. We should get people the care they need now.”

Among AAICAD 2010 attendees were several of the 45 AD researchers participating in the Alzheimer's Breakthrough Ride, which kicked off July 17 in San Francisco and will conclude September 21 (World Alzheimer's Day) in Washington, D.C. As the researchers bicycle across the United States, they are collecting signatures urging lawmakers to make AD a national funding priority. To track the progress of cyclists or sign the petition online, visit www.alz.org/breakthroughride.

To learn more about science news presented at AAICAD 2010 or about AAICAD 2011, which will take place July 16–21 in Paris, France, visit www.alz.org/icad.