The Fountain of Youth: Cultural, Scientific, and Ethical Perspectives on a Biomedical Goal
http://www.100md.com
《新英格兰医药杂志》
Is it possible to increase human longevity dramatically? And if so, at what price? By prolonging an old age of chronic disease and disability, mental incompetence, functional decline, and dependency, perhaps even sacrificing, in a devil's bargain, what it means to be human?
Such are the weighty questions debated in The Fountain of Youth, which was inspired by a 2002 multidisciplinary conference. This timely book, consisting of 17 chapters, a highly commendable annotated bibliography, and a review of selected primary articles, was assembled to review the history of the quest for extended and eternal life, the contemporary science of prolongevity, ethical and social perspectives on radical life extension, and the legitimacy of the antiaging movement.
The stage for this debate is well set in the section on the new science of prolongevity in the opening chapter by S. Jay Olshansky and Bruce Carnes, which offers a reasoned explication of the traditional, consensus model among biogerontologists — the evolutionary theory of longevity. According to this theory, the platform of aging of every person has been genetically determined by Darwinian forces of selection that favor perpetuation of the species through overall reproductive success, including some life extension into the postreproductive phase that facilitates survival of offspring until they, too, can reproduce. (Such longevity has semiseriously been called "the biological warranty period.") However, trade-offs favoring reproductive success have often come at the expense of overall longevity, both average and maximal. In modern civilization, as humans have been increasingly protected from hostile environmental forces, mean longevity creeps toward the upper limit of the human life span, which has been fixed at 122 years (at last count), and variance around that mean progressively narrows. Progress in this shift was most dramatic in the first half of the 20th century, primarily as a result of improved nutrition, education, sanitation, and other public health measures. Thereafter, increases have continued, albeit at a diminishing rate, and are attributable in roughly equal proportions to preventive lifestyle improvements and to medical interventions (imaging, pharmacology, medical care, and surgery — breathtaking advances, but at enormous expense). Optimally, these interventions may postpone sickness and decline until shortly before death, the attractive "compression of morbidity" theory popularized by James Fries.
Enter here the proponents of radical breakthroughs in life extension. Richard Miller argues that strategies such as caloric restriction (which has been classically demonstrated to increase longevity in rodents by 40 percent, a finding that has since been repeated in numerous species, including primates) might well increase average human longevity by a comparable degree — to 112 years, though preferably and practically through the ingestion of a pill. And if only we considered aging per se as a disease and funded prolongevity science accordingly, we might really begin to approach such an ambitious goal.
However, here the concerns of bioethicists and other social commentators enter the fray. Would achievement of such extreme longevity result in a "tragedy of the commons," in which individual, self-centered pursuit of maximal longevity would produce grave losses to society and the survival of our species as humans in the form of increased ageism, elitism, classism, racism, sexism, maldistribution of resources and justice, intolerance of diversity of all kinds, and intergenerational conflict? Perhaps this concern is most eloquently captured by Leon Kass, who argues passionately that "immortality for oneself through children may be a delusion, but participating in the natural renewal of humankind through children is not."
Finally, however, the authors are clear that they do not wish to debate, or become closely associated with, the antiaging movement (as championed by the American Academy of Anti-Aging Medicine, or A4M), choosing to distance themselves from those who might exploit the popular fantasies of those seeking the fountain of youth through unproven nostrums, superficial surgery, or other pseudoscientific approaches to life extension. Thus, the A4M and its 11,000 members would dismiss this book as another product of crusty, hidebound members of the "gerontological establishment."
Nevertheless, all told, I would highly recommend this book as a most readable, provocative, and informative primer for all serious observers of biogerontology (including geriatricians) as they examine the progressive aging of the world's population — a trend that is certain to pose a central challenge to 21st-century civilization.
William R. Hazzard, M.D.
University of Washington School of Medicine
Seattle, WA 98108
william.hazzard@med.va.gov(Stephen G. Post and Rober)
Such are the weighty questions debated in The Fountain of Youth, which was inspired by a 2002 multidisciplinary conference. This timely book, consisting of 17 chapters, a highly commendable annotated bibliography, and a review of selected primary articles, was assembled to review the history of the quest for extended and eternal life, the contemporary science of prolongevity, ethical and social perspectives on radical life extension, and the legitimacy of the antiaging movement.
The stage for this debate is well set in the section on the new science of prolongevity in the opening chapter by S. Jay Olshansky and Bruce Carnes, which offers a reasoned explication of the traditional, consensus model among biogerontologists — the evolutionary theory of longevity. According to this theory, the platform of aging of every person has been genetically determined by Darwinian forces of selection that favor perpetuation of the species through overall reproductive success, including some life extension into the postreproductive phase that facilitates survival of offspring until they, too, can reproduce. (Such longevity has semiseriously been called "the biological warranty period.") However, trade-offs favoring reproductive success have often come at the expense of overall longevity, both average and maximal. In modern civilization, as humans have been increasingly protected from hostile environmental forces, mean longevity creeps toward the upper limit of the human life span, which has been fixed at 122 years (at last count), and variance around that mean progressively narrows. Progress in this shift was most dramatic in the first half of the 20th century, primarily as a result of improved nutrition, education, sanitation, and other public health measures. Thereafter, increases have continued, albeit at a diminishing rate, and are attributable in roughly equal proportions to preventive lifestyle improvements and to medical interventions (imaging, pharmacology, medical care, and surgery — breathtaking advances, but at enormous expense). Optimally, these interventions may postpone sickness and decline until shortly before death, the attractive "compression of morbidity" theory popularized by James Fries.
Enter here the proponents of radical breakthroughs in life extension. Richard Miller argues that strategies such as caloric restriction (which has been classically demonstrated to increase longevity in rodents by 40 percent, a finding that has since been repeated in numerous species, including primates) might well increase average human longevity by a comparable degree — to 112 years, though preferably and practically through the ingestion of a pill. And if only we considered aging per se as a disease and funded prolongevity science accordingly, we might really begin to approach such an ambitious goal.
However, here the concerns of bioethicists and other social commentators enter the fray. Would achievement of such extreme longevity result in a "tragedy of the commons," in which individual, self-centered pursuit of maximal longevity would produce grave losses to society and the survival of our species as humans in the form of increased ageism, elitism, classism, racism, sexism, maldistribution of resources and justice, intolerance of diversity of all kinds, and intergenerational conflict? Perhaps this concern is most eloquently captured by Leon Kass, who argues passionately that "immortality for oneself through children may be a delusion, but participating in the natural renewal of humankind through children is not."
Finally, however, the authors are clear that they do not wish to debate, or become closely associated with, the antiaging movement (as championed by the American Academy of Anti-Aging Medicine, or A4M), choosing to distance themselves from those who might exploit the popular fantasies of those seeking the fountain of youth through unproven nostrums, superficial surgery, or other pseudoscientific approaches to life extension. Thus, the A4M and its 11,000 members would dismiss this book as another product of crusty, hidebound members of the "gerontological establishment."
Nevertheless, all told, I would highly recommend this book as a most readable, provocative, and informative primer for all serious observers of biogerontology (including geriatricians) as they examine the progressive aging of the world's population — a trend that is certain to pose a central challenge to 21st-century civilization.
William R. Hazzard, M.D.
University of Washington School of Medicine
Seattle, WA 98108
william.hazzard@med.va.gov(Stephen G. Post and Rober)