11.3 未来之路和基本概念

The coming era of precision medicine and the continued emphasis on improving the healthspan will have a significant effect on how we view aging. It remains unclear what role the individual who is 70 years old or older will have in this new social order. Some view the coming social changes as ushering in a time of great opportunity. These optimists suggest that in a society where the time to death is extended, significantly more freedom is gained to explore new possibilities without urgency and the constraints of time. Greater exploration and experimentation in the

arts, sciences, medicine, and other fields will ultimately lead to an expansion of human knowledge, thereby accelerating human progress. All of humanity will benefit. Other prognosticators are more pessimistic at the prospect of a healthier, longer life. Some suggest that a sense of urgency arising from a not-so-distant end of life is a powerful force, through which individuals feel the need to put their heart and soul into their work or ambition. It is this sense of urgency that underlies the progress of a society. A long, healthy life may remove that urgency and lead to less, rather than more, progress.

No one can say with certainty what society will become. Of course, that was not our point here. Rather, our hope is that you will have gained a greater appreciation for points of view that you may not have expected or experienced. Most of us may never have given thought to the idea that reducing or even halting research on how to retard aging and increase longevity might be an acceptable alternative to the current push for slowing the rate of human aging. If we accept that the pessimistic view has validity, then we must consider how valuable research on aging retardation is to society. Placing the research emphasis on curing disease and compressing morbidity within the life span we already have might be more valuable to humanity.

The reality is, however, that research into the slowing of aging will increase rather than decrease in importance. Suffering the maladies of disease and old age will remain repugnant to most humans, even if methods are discovered to compress this morbidity into just a few months. The average life span of humans will continue to increase, and the health of the older population will improve. The resulting increase in life span and healthspan will bring new and difficult challenges for our society. Any adverse effect on the individual can be kept at a minimum and be significantly less dramatic if we keep this discussion alive and allow room for all opinions. The science of biogerontology has a major role to play in this discussion.

ESSENTIAL CONCEPTS

• The aging population of the future will be characterized by extended youth and increased healthspan.

• Healthspan is the difference between the length of life and years spent free of disability.

• Measuring disability can be challenging because there does not exist a generally agreed upon definition for health and disability.

• Morbidity, activities of daily living (ADL), physical functionality, and biological markers have all been used as measures of disability.

• Until a true biomarker of aging has been validated, measuring disability resulting from time-dependent function loss will remain imprecise and open to debate.

• An exclusive focus on treating or curing chronic disease cannot be expected to significantly decrease disability in the older population.

• Interventions that postpone the effects in the mechanism of aging will be the best path to reducing disability in the older population.

• The passage of time and the natural laws of the universe are the underlying causes of chronic disease and physiological decline.

• Although exercise and low-calorie diets postpone the effects in the mechanisms of aging and extend healthspan, participation in these two healthspan-increasing treatments remains low and declines with age.

• Lack of scientifically accurate and specific exercise and diet protocols leads to low participation levels.

• Most economically developed nations have begun the process that will eventually lead to prescribable protocols for exercise and diet.

• A physician's authority to prescribe means that exercise and dietary protocols have been approved by a review panel of experts as being safe, scientifically accurate, and effective.

• Since governments and insurance companies are more likely to cover cost of exercise and dietary protocols if they are deemed safe and effective, the economic barriers to a healthier lifestyle will be lessened.

• Medical interventions, pharmaceuticals, gene therapies, tissue replacement, etc., are being developed that postpone the effects in the proximal mechanisms of aging.

• Postponing the effects in the proximal mechanisms of aging will require that the treatment be highly individualized and capable of affecting multiple mechanisms of aging simultaneously.

• Medications affecting multiple proximal mechanisms of aging will be introduced after quantitative methods associated with precision medicine replace the observational science of diseasecentered medicine.

• The shift from an exclusively young-oriented culture to one that includes all age groups will profoundly affect the basic structure and norms of society.

• A healthier and longer life may encourage individuals to engage in projects or new ventures that are beyond reach in a shorter life. That is, individuals will have greater opportunities to achieve their goals and ambitions.

• Some experts believe that healthier and longer life spans will disrupt our sense of achievement. If individuals know they have time for a redo, they may be less inclined to commit to a particular goal. Giving up too early may become a way of life.

• A healthier and longer life means that couples can wait to have children, giving them more time to explore life's options before committing to childrearing.

• Extended healthspan could result in individuals participating in the workforce well into their seventies and eighties. These individuals will maintain high-level positions and cause younger individuals to stagnate in lower management positions. Our concept of what it means to be a productive member of society will be challenged.

• Overall, increased healthspan and the prospect of extended life spans will challenge our concepts of personal achievement, when to have children, and the generational structure of the family and society.

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