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FY 2002 Hearing on Lifespan

Richard J. Hodes, M.D.
National Institute on Aging

April 4, 2001 

Mr. Chairman and Members of the Committee:

Thank you for inviting me to appear before you today along with my distinguished colleagues from the National Institutes of Health (NIH). I am Dr. Richard Hodes, Director of the National Institute Aging (NIA), and it is an honor to share information with you about what we are learning through biomedical, behavioral and social research to improve the lives of older people.

In contrast to negative stereotypes of later life characterized by increasing disability, disease and economic hardship, older Americans are generally better off—healthier and wealthier—than ever before. Americans are also living longer than ever before. Life expectancy in the United States has dramatically improved from an average of 49 years in 1900 to 76 years at the turn of the 21st century. In addition to increased life expectancy, improvements in the health status of older Americans have also been observed. Between 1994 and 1996, 72% of Americans 65 and older reported their health as good or excellent. Despite this promising news, we know that good health is not a universal reality for all older Americans—especially for aging minority groups.

Thus, the NIA is committed to supporting high quality research to enhance our understanding of the challenges older people face and to develop interventions for the conditions and diseases that strike the elderly—particularly interventions that could be adopted throughout the life cycle.

The Declining Disability of Older Americans

Some of the most promising news of the last decade has been the decline in the observed rate of disability for people 65 years and older. (Chart #1) In a landmark study, researchers used the 1982 disability rates from the National Long Term Care Survey (NLTCS) for people 65 and older to estimate the numbers of disabled persons in each future year using census bureau projections. They then used subsequent waves of the NLTCS to determine the actual numbers of disabled persons and compared that to their estimates. Using this method, they observed 1.6 million fewer disabled older people in the U.S. in 1998 than there would have if the disability rate had not changed since 1982. These decreases in disability have been confirmed using multiple databases and have been shown to benefit both men and women, and minority as well as non-minority populations. The latest preliminary findings from the 1999 NLTCS suggest that the rate of decline in chronic disability is continuing and may be accelerating.


Research is ongoing to understand the potentially significant long-term economic and social consequences of disability decline, including its effect on health care costs and the American workforce. Importantly, research has also begun to identify the factors contributing to the decline so that specific interventions and behavioral changes can be designed that might sustain or accelerate trends in improved function and quality of life among older Americans.

Conquering Alzheimer's Disease

To improve the quality of life and health of older people it is imperative that strategies for addressing Alzheimer’s disease (AD) be developed. AD, the most common cause of dementia among older persons, tragically affects as many as four million Americans who are predominately 65 years and older. Although it is not known what causes AD, there has been an explosion of recent findings that are yielding important clues about AD risk factors and disease pathology and, as a result, are suggesting targets for treatment and prevention.

In the past year, scientists have identified a number of genetic and non-genetic AD risk factors. Examples of non-genetic risk factors include poor socioeconomic status, educational level, and history of serious head trauma. Evidence from these and other studies suggests that early life course events may play a role in AD development and could lead to novel strategies for addressing AD across the lifespan.

While research is ongoing to explain how AD develops, scientists are also developing effective AD treatments. Many of the treatments currently being tested evolved from advances in basic research. The discovery of two enzymes, beta and gamma secretase, which are involved in the clipping of a normal cell surface protein to produce the amyloid peptide that forms the senile plaques found in the brains of AD patients, is leading to development of drugs to block activity of these enzymes and to slow amyloid production. In an exciting new immunological approach to slowing accumulation of amyloid plaques, researchers are developing and testing different versions of an amyloid vaccine. In a breakthrough experiment last year, pharmaceutical company scientists showed that repeated long-term injections of an amyloid vaccine can stimulate an immune response in test mice, nearly eliminating amyloid plaques and associated neuropathology. (Chart #2) A number of NIH-funded scientists have confirmed and extended these observations and have shown that the vaccine is effective in preventing cognitive decline in mice. Human trials are now beginning to test both the safety and efficacy of these vaccines as a possible therapy for AD.

Immunization with Reduces Deposition in Hippocampus of Mice and Prevents Memory Deficit

A large number of compounds are presently being tested or will soon be tested in human AD clinical trials being sponsored by the public and private sectors. The NIA is currently supporting 17 AD clinical trials, seven of which are large-scale cognitive impairment and AD prevention trials. These trials are testing agents, such as estrogen, anti-inflammatory drugs, and anti-oxidants, for their effects on slowing progress of the disease, delaying AD’s onset, or preventing the disease altogether. Prevention trials are the among the most costly of research projects, but, if successful, the payoff in terms of reduced disease and disability will be significant.

Reducing Chronic Disease and Disability

Besides AD, chronic disease and disability can compromise the quality of life for older people. Some 79% of people age 70 and older have at least one of seven potentially disabling conditions (arthritis, hypertension, heart disease, diabetes, respiratory diseases, stroke, and cancer). The NIA is supporting a variety of research activities to develop treatment and prevention strategies for all of these conditions. One intervention that has been shown consistently to be effective in maintaining health and function and decreasing disability is exercise. Despite the benefits of exercise, which include reducing the risk of heart disease, preventing osteoporosis, relieving moderate depression and improving pain management, people, young and old, are not fully participating in physical fitness programs. While the NIA continues to support research to more fully understand the physical benefits of exercise, the Institute is also supporting research to understand what motivates older people to engage in and comply with a regular exercise program. The Institute is translating these findings into its ongoing exercise campaign to encourage older people to exercise. Physical fitness is an issue that bridges generations and is a cross-cutting area of interest on which the NIH Institutes and Centers are collaborating.

Understanding and Extending the Lifespan

To understand the aging process, it is important to identify those factors that affect the overall lifespan of an organism. Toward this end, NIA supports and promotes research on the biochemical, genetic, and physiological mechanisms of aging and the onset of age-related disease. Experiments in a number of animals models, such as mice, fruit flies, and nematodes (roundworms), are providing valuable insights.

In all of these organisms, caloric restriction, which entails a diet that includes all of the necessary nutrients but fewer calories, has been shown to slow the intrinsic rate of aging and to delay and reduce the onset of diseases, such as cancer. In rodents, it was demonstrated that caloric restriction can also increase resistance of neurons to age-related and disease-specific stresses, suggesting that it may be an effective approach for reducing neuronal damage and neurodegenerative disorders in aging. Although the effects of caloric restriction on humans have not been evaluated, it is conceivable that one day we will understand the effects of this intervention on people and whether or not it is a potential strategy for increasing healthy lifespan in humans.

Genetic research is also helping to unlock the mysteries of longevity and good health. Research has identified genes that are associated with increasing lifespan in nonmammalian species and human beings, and researchers are utilizing sophisticated microarray technology to more fully understand gene activity, allowing analysis of many thousands of genes at once. Microarray technology is providing insights to longstanding questions about the molecular mechanisms of aging and may eventually provide useful biomarkers of aging that can be used to assess the effectiveness of strategies to retard aging-related processes.


By the year 2050, the U.S. Census Bureau estimates that there will be over 80 million people 65 years and older living in the United States. To ensure that these Americans reap the benefits of a longer life, the urgency of developing successful interventions to address diseases and conditions associated with advanced age is paramount. Ideally, these interventions should be applicable throughout the lifespan, giving people hope and approaches for realizing vitality in later life. The progress made in the last century to improve the health and socioeconomic status of our nation’s elders demonstrates that we have the capacity to achieve ambitious goals. I look forward to working with my colleagues at NIH and the scientific community towards continuous improvement of the health and well-being of older people in America.

1 National Center for Health Statistics, National Vital Statistics Report, United States Life Tables, 1998, February 2001.

2 Federal Interagency Forum on Aging Related Statistics. Older Americans 2000: Key Indicators of Well-Being. 2000.

3 National Long Term Care Survey 1982-1994 (Kenneth Manton, Ph.D.)

4 National Center for Health Statistics, Health, United States, 1999 With Health and Aging Chartbook. Figure 11, pg. 41. Hyattsville, MD: 1999.

Page last updated Sep 26, 2008