Introduction
 These days, it seems that newspapers, magazines, and TV are full of stories about ways to stay healthy, eat right, and keep fit. Lots of people are concerned about staying healthy as they get older. They wonder whether they can do anything to prevent diseases that happen more often with age, such as Alzheimer's disease (AD). AD has no known cure, and the secrets to preventing it are not yet known. But research supported by the National Institute on Aging (NIA) and other public and private agencies offers tantalizing clues about the origins and development of AD. These findings are raising hopes that someday it might be possible to delay the onset of AD, slow its progress, or even prevent it altogether. Delaying by even 5 years the time when AD symptoms begin could greatly reduce the number of people who have the disease.
The National Institute on Aging, part of the Federal Government's National Institutes of Health, has primary responsibility for research on AD and age-related decline in cognitive abilities (such as thinking, decision-making, and language skills). This responsibility is part of a larger mission to understand the nature of aging and find ways to help people stay physically, emotionally, and cognitively healthy for as long as possible.
 Several years ago, NIA, the National Institute of Mental Health, and the National Institute of Neurological Disorders and Stroke launched The Cognitive and Emotional Health Project, which has begun to identify and describe the diverse lifestyle factors that possibly affect the emotional health and cognitive abilities of older adults. Further research on the most promising factors will be necessary to determine whether any will result in strategies that can help people remain mentally and emotionally vibrant as they age. The hope is that successful strategies will also contribute to our knowledge of what goes wrong in the brain during the development of neurodegenerative diseases like AD.
1. Preventing a Complex Disease Like AD is a Challenge
Many diseases, such as diabetes, heart disease, and arthritis, are complex. They develop when genetic, environmental, and lifestyle factors work together to cause a disease process to start and then progress. The importance of these factors may differ for each person. AD is one of these complex diseases. It develops over many years, and it appears to be affected by a number of factors that may increase or decrease a person's risk of developing the disease. We don't have control over some of the risk factors for AD. We can do something about other possible AD risk factors, though. The effect on any particular person of risk factor changes will likely depend on his or her genetic makeup, environment, and lifestyle.
2. AD Risk Factors We Can't Control
Age is the most important known risk factor for AD. The risk of developing the disease doubles every 5 years over age 65. Several studies estimate that up to half the people older than 85 have AD. These facts are significant because of the growing number of people 65 and older. More than 34 million Americans are now 65 or older. Even more significant, the group with the highest risk of AD-those older than 85-is the fastest growing population group in the country.
Genetics is the other known AD risk factor that a person can't control. Scientists have found genetic links to the two forms of AD. Early-onset AD is a very rare form of the disease that can occur in people between the ages of 30 and 65. In the 1980s and early 1990s, researchers found that mutations (or changes) in certain genes on three chromosomes cause early-onset AD. If a parent has any of these genetic mutations, his or her child has a 50-50 chance of inheriting the mutant gene and developing early-onset AD.
Late-onset AD, the more common form, develops after age 65. In 1992, researchers found that certain forms of the apolipoprotein E (APOE) gene can influence AD risk:
APOE-ε2, a rarely occurring form, may provide some protection;
APOE-ε3, the most common form, plays a neutral role; and
APOE-ε4, which is found in about 40 percent of people with AD; APOE-ε4 lowers the age of onset and thus increases risk. (Having this gene form does not mean that a person will definitely develop AD; it only increases risk. Many people who develop AD do not have the APOE-ε4 form.)
|
[ 1 ] |
[ 2 ] |
[ 3 ] |
[ 4 ] |
[ 5 ]
|
Next page |
to top of page
|
