New report suggests promising strategies to preserve brain health as people grow older

Feb 24 2006

With the rapid aging of the population, the National Institutes of Health (NIH) is intensifying the search for strategies to preserve brain health as people grow older.

The effort moved an important step forward with a report by an expert panel to the NIH, suggesting a number of promising avenues for maintaining or enhancing cognitive and emotional function. Specifically, the group said, education, cardiovascular health, physical activity, psychosocial factors and genetics appear to be associated with brain health with age, and research aimed at directly testing the effectiveness of interventions in several of these areas deserves further attention.

The report is published online in Alzheimer's and Dementia: The Journal of the Alzheimer's Association. It is a product of the Critical Evaluation Study Committee, a panel of experts appointed by NIH and led by Hugh Hendrie, M.B., Ch.B., D.Sc., of Indiana University, Indianapolis. The committee evaluated several large on-going studies of older adults for current scientific knowledge on brain health.

"Three NIH institutes--the National Institute on Aging (NIA), the National Institute of Mental Health (NIMH) and the National Institute of Neurological Disorders and Stroke (NINDS)--established the NIH Cognitive and Emotional Health Project to coordinate and accelerate research leading to interventions for neurological health," says NIH Director Elias A. Zerhouni, M.D. "This report suggests a future direction of research and is a terrific example of what we can learn when scientists of diverse specialties work together on a complex health issue."

Hendrie and colleagues cited demographic pressures to find ways to maintain cognitive and emotional health with age. Approximately 4.5 million Americans have Alzheimer's disease, and additional numbers of older people experience less severe, but still problematic cognitive impairment with the risk of such cognitive decline increasing with age. In one area of emotional health - depression - the everyday function of an estimated two million older adults is also threatened, according to NIMH.

"With more Americans living well into their 70s, 80s and 90s, developing strategies to preserve cognitive and emotional health as we grow older is a major public health goal," says Richard J. Hodes, M.D., Director of the NIA. "This report analyzes research identifying factors that are associated with cognitive and emotional health and most importantly describes several directions for testing interventions to determine their effectiveness in improving cognition and emotional health."

The panel broadly discussed a change in the focus of brain research. In addition to studying specific causes of brain disease and dysfunction, research also should approach cognition and emotion from the opposite direction--looking at what works to preserve brain health. "We set up the Cognitive and Emotional Health Project in recognition of changed thinking. In this report, the committee specifically articulates a new paradigm for research focused on health rather than dysfunction," says NINDS Director Story C. Landis, Ph.D.

Another major theme emphasized the interconnectedness between cognitive and emotional health. Cognitive health and emotional well-being are "inextricably linked," the report concludes, and efforts should be made to examine them simultaneously.

"Cognitive decline and emotional stress in older people involve a number of physiological and psychological processes going on at the same time," says Thomas Insel, M.D., Director of NIMH. "This report highlights the need to better understand this interrelatedness if we are going to devise effective ways to maintain brain health."

The evaluation committee reviewed scientific data from 36 large, ongoing studies of aging and identified more than 40 separate factors that may play a role in cognitive and emotional health. Those highlighted in the report are summarized below, including those in which possible interventions might be explored:

• Education - Higher levels of education correlate with both good cognitive and emotional function in the scientific literature. But there is no consensus as to why this may be so. Researchers continue to explore such explanations as education providing cognitive "reserve" or the socioeconomic factors such as quality of education that may affect the relationship between higher education and better cognition.
• Cardiovascular--A growing body of observational research links cognitive decline with several traditional risk factors for cardiovascular disease, including hypertension, greater body mass index, heart disease, diabetes and smoking. Understanding the impact of these influences is critically important because they can be modified though lifestyle and medical interventions. NIH currently funds clinical trials to test whether interventions for high blood pressure, diabetes and high cholesterol reduce the risk of cognitive decline.
• Psychosocial--A number of psychosocial factors--emotional and social support networks, high socio-economic status and low stress levels--correlate with cognitive and emotional health later in life. Stress, for example, has been linked to cognitive decline, while social engagement, social support and higher socio-economic status are associated with better cognitive and emotional health.
• Depression and anxiety --Some studies associate a history of depression or anxiety with poor cognitive and emotional health later in life. Researchers only recently have recognized a possible connection between mood disorders and future cognitive decline. This could be an important area for testing interventions.
• Physical activity--Finding out if physical activity can protect against cognitive deterioration "would be of great public health importance because physical activity is relatively inexpensive, has few negative consequences, and is accessible," the report says. A number of studies suggest a protective effect, and clinical trials are underway to test exercise as an intervention against cognitive decline. The panel said a large clinical trial should be considered.
• Chronic illness--Chronic illnesses, such as arthritis, cancer, lung disease, heart disease and diabetes, are linked to poor emotional outcomes, specifically depression, in older people. Further study could examine the important questions of cause and effect, whether illness causes depression or whether depression can make people more vulnerable to illness.
• Genetics--There is a poor understanding of genetic influences on cognitive and emotional health. While risk for late-onset Alzheimer's disease increases with inheriting one form of the apolipoproteinE (APOE) gene, little is known about its specific role in Alzheimer's or its effects on emotional health. Genetic factors cannot be modified, but greater knowledge of the genetics of cognitive and emotional health could help identify people at higher risk.

Details of the research papers evaluated by the panel are available online at http://www.biostat.iupui.edu/~sgao/healthybrain/hblogin.asp. The Cognitive and Emotional Health Project's searchable database of a large number of studies on age and cognitive and emotional function can be found on the NIH website at http://trans.nih.gov/CEHP.