The most conservative members of the aging research community don't believe that human life spans can be meaningfully extended any time soon, or that we should even make the attempt. Fortunately, they don't have much more to say on the matter, so don't contribute meaningfully to discussions on this topic within the scientific community. They are a part of the silent majority: researchers who only investigate aging, gathering data rather than attempting to do something about it.
Among scientists who do believe that lives can be lengthened, most - in public at least - adhere to the view that the only plausible goal is a gentle slowing of the pace of aging, and that even this is not going to happen any time soon. The proposed methodologies here generally involve ways to shift the operation of metabolism into more efficient states, such as that produced through the practice of calorie restriction, shown to extend healthy and maximum life spans in many different species. As the past few decades of research have demonstrated, this is an expensive and complex proposition. Despite billions of dollars in research funding, there is little to show yet beyond an increased understanding of the relationship between metabolism, genetics, and natural variations in longevity - and that present understanding is clearly just a starting point.
(Fortunately there is a much better way forward based on identifying and repairing the damage that causes aging. Such an approach doesn't require anywhere near as much new knowledge, and will lead to rejuvenation rather than just a slowing of aging. As yet this is a minority research program within longevity science, however, for all that it is the self-evidently better path forward. But that is not today's topic).
Among researchers who look with favor on work aimed at gently slowing aging, there is one group who have for some years promoted what they call the Longevity Dividend: a proposal for large-scale public funding to go towards methods of slowing aging. Their position is backed by models that show incrementally greater gains in health than can be achieved through the present modus operandi of trying to patch over age-related diseases in their late stages. At the highest level this is a matter of prevention versus cure: aging is the cause of age-related diseases, and thus efforts focused on treating aging should be far more efficient when it comes to raising quality of life and reducing the incidence and cost of frailty and disability in the old.
The Longevity Dividend camp has gathered supporters over the years, as open discussion of extending human life has become more acceptable within the scientific community, and this example of research and advocacy is their latest foray into the public funding arena:
Medical advances, improved nutrition, and reductions in smoking have extended life expectancy and reduced the prevalence of diseases that stalk modern society. Paradoxically, though, for every success, an equally difficult challenge remains. As people age, they are less likely to suffer through a single disease but rather experience multiple maladies related to living longer. In this issue of Health Affairs we explore this paradox and many other subjects while conceding that humankind will never exhaust the quest for reducing mortality and relieving pain.
Are there other approaches to prolonging healthy living that could accompany these ongoing efforts? Dana Goldman, David Cutler, John Rowe, Pierre-Carl Michaud, Jeffrey Sullivan, Desi Peneva, and Jay Olshansky have developed a hypothetical alternative called "delayed aging." Their article reports that studies with animal models have shown real potential and concludes that greater investment in research on delaying aging appears to be an efficient way to forestall disease, extend healthy life, and improve public health.
Recent scientific advances suggest that slowing the aging process (senescence) is now a realistic goal. Yet most medical research remains focused on combating individual diseases. Using the Future Elderly Model - a microsimulation of the future health and spending of older Americans - we compared optimistic "disease specific" scenarios with a hypothetical "delayed aging" scenario in terms of the scenarios' impact on longevity, disability, and major entitlement program costs.
Delayed aging could increase life expectancy by an additional 2.2 years, most of which would be spent in good health. The economic value of delayed aging is estimated to be $7.1 trillion over fifty years. In contrast, addressing heart disease and cancer separately would yield diminishing improvements in health and longevity by 2060 - mainly due to competing risks. Delayed aging would greatly increase entitlement outlays, especially for Social Security. However, these changes could be offset by increasing the Medicare eligibility age and the normal retirement age for Social Security. Overall, greater investment in research to delay aging appears to be a highly efficient way to forestall disease, extend healthy life, and improve public health.
"When we treat someone with cancer, or heart disease, or stroke, we are treating a manifestation or byproduct of biological aging -- the underlying process marches on unaltered by this approach to disease," said Jay Olshansky, a professor at the University of Illinois School of Public Health in Chicago and a co-author of the study. "This means that even if we succeed for a time in extending life by treating disease, either that disease or another will emerge with time....Slowing aging alters the risk of all diseases simultaneously by attacking the origins of all of the things that go wrong with us as we grow older."
With even modest gains in our scientific understanding of how to slow the aging process, an additional 5 percent of adults over the age of 65 would be healthy rather than disabled every year from 2030 to 2060, reveals the forthcoming study. Put another way, an investment in delayed aging would mean 11.7 million more healthy adults over the age of 65 in 2060.
The analysis, from top scientists at USC, Harvard, Columbia, the University of Illinois at Chicago and other institutions, assumes research investment leading to a 1.25 percent reduction in the likelihood of age-related diseases. In contrast to treatments for fatal diseases, slowing aging would have no health returns initially, but would have significant benefits over the long term.
This is all very encouraging from the point of view that more public discussion of extended longevity through medical science is a good thing. A rising tide floats all boats. But attempting to slow aging is a great way to burn a lot of money and time with the expectation of very little to show for it at the end of the day. This isn't rejuvenation research of the sort advocated by the SENS Research Foundation, and only that type of repair-based strategies for treating aging have the possibility of producing the means of human rejuvenation soon enough to matter. The expected outcome for drug development to slow aging is that everyone in middle age today will age to death on much the same schedule as their parents: the emergence of treatments to slightly slow aging twenty years from now, produced at a vast cost, will do next to nothing to change that outcome.
Aging is damage, and only by repair of that damage can aging be reversed. So be appropriately pleased to see more discussion of extending healthy life in public, but recognize that only greater material support for SENS research and similar programs will help us live for decades longer in good health.