S. Jay Olshansky, John Beard and Axel Börsch-Supan
The ageing of humanity is accelerating. While a small number of people is known to have lived to extreme old age throughout recorded history, it is only in the modern era that an unprecedented number is approaching old age with regularity.
In the past, the main challenges to human health and longevity were maternal mortality and communicable diseases that struck early in life; both denied access to old age for the vast majority of people. In developed nations today, and among increasingly larger subgroups of the population in less-developed nations, between 80% and 90% of all
babies born will survive past age 65.1 Combined with falling fertility,
these trends mean that older people are now a much larger and rapidly growing proportion of populations around the globe. This trend is likely to continue until at least the middle of this century.
Some authors view this radical transformation in our demographics from
an overwhelmingly negative perspective,2,3 where population ageing is
often portrayed as a form of apocalyptic demography. In their narrative, older people are perceived and portrayed only as sick and costly members of society – threatening to strain national economies, overwhelm health care systems, and bankrupt public pensions.
Hence, a strategy to fully exploit the secular change in life course health patterns requires action in two dimensions. First, we need to adapt our social and economic institutions to encourage health improvements at younger ages. Second, enough is now known about the etiology and treatment of most chronic diseases that, if identified and dealt with early enough, the maladies of old age could represent, for many, little more than nuisances requiring adaptation in the later stages of an otherwise healthy life.
Older Generations – an Underutilized Resource
The extension of healthy life is a great economic advantage to individuals and populations because the most important economic resource is the human capacity to produce goods and services – some within the family and society without pay, such as help and volunteer work, and most via markets and for pay. Extending the years of healthy life creates additional capacity, part of which can be used to finance higher healthcare and pension costs.
Often, however, we do not utilize these resources as we could. The dramatic improvement in health at younger ages, and the dynamics of the late onset of functional disabilities due to the “new” chronic diseases, are in stark contrast to our static concepts of the life course transitions, which have developed over the past century or so. These still follow a familiar trajectory: birth; growth and development; education; entrance into the labour force for a single lifetime career; marriage and family; grandparenthood and retirement. This linear ordering, and at set times, may have been appropriate at a particular stage of our social evolution, but the dramatic demographic changes now occurring give pause to reconsider the rigidity of this model.
The concept of retirement transition, in particular, has been remarkably stable across time and countries, and appears unrelated to past and current successful efforts at extending life. Even stronger, labour force participation has fallen dramatically after age 55 in most developed countries since the 1970s and only recently has stabilized.7 The same holds true in most developing countries for the government sector, often the only sector with a formal pension.
It is a great irony of our times that labour force participation at older ages is low in countries and sectors where people are rich and healthy, while those who are poorer and less healthy tend to work in agricultural or informal jobs such as street vendors until very late in life Why is the ability to work so vastly underutilized among the richer and healthier? One rationale often cited, especially by labour unions and to support the idea that older people are an economic burden, is the belief that removing them from the labour force helps to create job openings for the young. This is wrong (the so-called “lump-of-labour fallacy”) because it assumes a zero-sum game and ignores the high costs of early retirement that have to be borne by younger workers, making older workers appear to be more expensive and thus less likely to be hired. In fact, countries with a higher labour force participation of older workers have a lower youth unemployment rate.8
Another reason for the underutilization of older people is the prejudice that they are less productive than younger people simply because they are older. There is no scientific evidence to support this belief. Rather, modern technology and the dominance of the service industry over manufacturing and agriculture have equalized productivity across age ranges. While speed and dexterity have been shown to decline as a function of age, this is more than compensated for by increases in experience and even-handedness that often occur at the same time. A third cause, from an employer’s point of view, is that it is often cheaper for a business to discard older people than younger ones, due to strong incentives in the pension system.9
Finally, one might think that early retirement is a well-deserved choice for more leisure and freedom from an unwanted job. However, the desire for early retirement is less widespread than often thought. Surveys suggest that about one-third of retirees would have preferred to work longer, but were forced to stop either by poor health or employer policies that required leaving a position due exclusively to chronological age. Another one-third had hoped to become involved in a different kind of
occupation upon retirement, often volunteer work, but for many such opportunities were hard to find or required more effort than previously expected. A core strategy for reaping dividends associated with the extension of healthy life is the development of policies to foster the active participation of healthy individuals over age 55 in formal work and informal volunteering.
However, while most people up to age 70, or even beyond, in developed countries – and many in developing countries are indeed healthy – less- than-perfect health does prevent some older people from working. Another element in a strategy to claim the longevity dividend is, therefore, improving the health of those 55- to 70-year-olds who are not very healthy. Taking Europe as an example, improving the health of the sickest one-fifth of the population to the level of the second-sickest fifth would raise labour force participation among people aged 50 and older by about 10%.
More ambitiously, it is worth considering that underlying most of what goes wrong with our bodies as we grow older are underlying biological processes of ageing that advance regardless of the diseases that are commonly expressed throughout the life course. Even if deaths from most major killers today are reduced dramatically, the biological processes of ageing march on, unaltered by any progress we make against specific diseases. Of course, this process is not entirely unrelated to chronic disease, because age is the strongest risk factor for almost all of these individual conditions.
This disjointed concept of ageing and disease has evolved into its current form only in the modern era and poses both a dilemma and an opportunity. If society can reduce mortality rates from chronic diseases, we are likely to enjoy moderately longer lives in better health. However, because ageing itself is unaltered by simply reducing the risk of disease, this approach is likely to run out of steam and eventually yield diminishing gains in both health and longevity.
By contrast, the opportunity that is before us arises from knowing that the biological process of ageing is a risk factor for most of what goes wrong with us as we grow older. Slowing down the processes of ageing – even by just a moderate amount – will yield dramatic improvements in health for current and all future generations. Furthermore, evidence from scientists who study the biology of ageing suggests that this is a plausible goal for modern medicine in the near term.20,21,22 Advances in the scientific knowledge of ageing may thus create new opportunities that allow us, and generations to follow, to live healthier and longer lives than our predecessors. We have reached a historical moment, as scientists learn more about slowing the underlying processes of ageing, to postpone a wide range of fatal and disabling diseases expressed throughout the lifespan. The result, if successful, would be health and economic benefits for current and all future generations.
There have recently been enough important new advances in this area of science that some find it reasonable to conclude that the technical means to slow ageing in people is a plausible goal. For example, research has dispelled the old belief still held by some that ageing is an immutable process that was genetically programmed by evolution.23 Indeed, because there can be no ageing or death genes that arose under the direct force of evolution,24,25 interventions designed to slow ageing in people may have fewer genetic barriers to success than might be otherwise expected. At least some of the manipulations that appear to slow ageing in animal models do just this, maintaining excellent physical and cognitive functioning well beyond the usual ages at which illness and disability start to affect most untreated individuals.26 In fact, interventions that slow ageing have the potential to do what no surgical procedure, behaviour modification or cure for any one major fatal disease can do; namely, extend youthful vigour throughout the lifespan. Combined, these new approaches to health promotion, disease prevention and ageing itself have been referred to as the pursuit of the “longevity dividend”,27 although the idea of slowing ageing is not
new.28,29,30,31 This notion is complemented by other scientists who have
documented the economic benefits associated with rising life expectancy32,33 and discussed the prospects of success in slowing ageing and the various benefits that would accrue to society as a result.34,35,36
Life Course Investments in the Health of Older Populations
In high-income countries, 94% of the “burden of disease” results from chronic disease and injury,10 and, even in low- and middle-income countries, chronic disease and injury are already the major causes of disease burden. These problems are caused by a combination of genetic susceptibility and, importantly, behaviours and exposures acquired throughout the life course. In fact, diseases expressed among older people today are often a product of events that began much earlier in life, including those caused by events over which we have no control (e.g., the physical, social, and economic environments into which we are born), and those that we modulate through lifestyle choices.
Health events influenced by the choices we make represent the low-hanging fruit of public health, because a significant proportion of the current burden of disease can be reduced by delaying or preventing chronic diseases through interventions to promote healthy behaviours, or by the early detection and management of either the disease or its behavioural risk factors. Classic examples include smoking and the rise of adult-onset and childhood-onset overweight and obesity. Policies to discourage the adoption of smoking, such as taxing cigarettes, or to encourage existing smokers to quit, will reduce the subsequent risk of much chronic disease.11
Because good health in older age is not achieved in isolation from the rest of the life course, investments now in health at younger and middle ages are therefore likely to yield a healthier and longer-lived older population in the future. Thus, a sound strategy for investing in the health of older people requires both a life course perspective that addresses the immediate needs of people who have already reached older ages, and a strategy designed to promote healthy behaviours earlier in life so that younger cohorts today can be healthier when they reach older ages in the future.12
These should include policies that promote healthy behaviours; education throughout the life course; regular screening for risk factors and early treatment to minimize the consequences of chronic disease; the effective management of more advanced disease through tertiary care and rehabilitation; the creation of age-friendly environments that foster both a healthy lifestyle at younger, middle and older ages; and the active participation of older people in society.13
A New Way to Invest in Health
There are still many unknowns related to the future course of health and longevity. While it is clear that most nations have extended lives,14 it is uncertain how much longer this trend can continue.15 Furthermore, there is mounting evidence that some populations or population subgroups may be on the verge of a decline in life expectancy because of worsening health among recent cohorts approaching retirement ages,16 while other subgroups could experience life-expectancy increases that extend beyond current official government forecasts.17 Perhaps more importantly, it is uncertain whether the added years of life that are a recent product of investments in life extension are going to be healthy or unhealthy.18
What is complicating the portrait of health and longevity today is the current medical model that approaches chronic degenerative diseases in much the same way communicable diseases were addressed more than a century ago – one-at-a-time,as they arise. The underlying premise of this model is that all diseases are treated as if they are independent of each other19 – having their own independent origin and etiology. Scientists know this is not true. Many of the behavioural risk factors for chronic disease relate to more than one condition, and even the physiologic mechanisms are not
Conclusion
Investing in health is equivalent to any other type of investment in human capital – it has the potential to generate substantive health and
economic dividends. However, for policy-makers to tap into the vast wealth of current and future generations of older persons, they are first going to have to dispel the myth that older people are only a drain on society. We suggest here that the best way to unlock the huge social and economic resources of an ageing population is to invest in health throughout life, and then to ensure social adaptation that fosters the ongoing contribution of these resources. A full life course perspective is required that understands and appreciates how investments in health at all ages produce health and economic benefits today and for
generations to come.
Two types of investments in health are warranted, and we contend that both should be pursued simultaneously. One involves a life course perspective where investment in improved health among older people is achieved by encouraging improvements in behavioural risk factors at all ages and by the early detection and treatment of chronic disease. This investment will ensure that healthy ageing becomes possible for current older generations, as well as for younger generations that will benefit immediately while they are young and then later in life as they grow older. The second investment is to attack the seeds of biological ageing itself as a way to postpone all of the infirmities of old age simultaneously. The latter approach requires modern medicine to understand and appreciate the weapon that research on ageing represents for its ability to postpone the diseases that accompany old age. Because prolonged, chronic illness is a powerful driver of medical costs, enormous cost savings would also be achieved if mortality and morbidity could be compressed within a shorter duration of time at the end of life.
Extending the duration of physical and mental capacity would permit people to remain in the labour force longer, amass more income and savings, and thereby lessen the effect of shifting demographics on age-based entitlement programmes, with a net benefit to national economies for those now alive and for all future generations.
Endnotes
1 Human Mortality Database. (2012) www.mortality.org
2 Kotlikoff, L. & Burns, S. (2005) The Coming Generational Storm. Cambridge: MIT Press. 3 Peterson, P. (2000) Gray Dawn. New York: Three Rivers Press.
4 Olshansky, S.J., Perry, D., Miller, R.A. & Butler, R.N. (2006) In pursuit of the Longevity Dividend. The Scientist, 20(3), 28-36.
5 Butler, R.N. et al. (2008) New model of health promotion and disease prevention for the 21st century. British Medical Journal, 337, 149-150.
6 Riley, J.C. (2001) Rising Life Expectancy: A Global History. Cambridge University Press. 7 Whitehouse, E. & Queisser, M. (2007) Pensions at a Glance: Public policies across OECD
countries. Available at: http://mpra.ub.uni-muenchen.de/16349/
8 Gruber, J. & Wise, D. (2001) An International Perspective on Policies for an Aging Society. NBER Working Paper, No. 8103.
9 Gruber, J. & Wise, D., eds. (1999) Social Security and Retirement Around the World. Chicago: University of
Chicago Press.
10 Lopez, A.D. et al. (2006) Global and regional burden of disease and risk factors, 2001: systematic analysis of population health data. Lancet, 367, 1747-57.
11 World Health Organization & World Economic Forum. (2011) From Burden to “Best Buys”: Reducing the Economic Impact of Non-Communicable Diseases in Low- and Middle-Income Countries. Geneva: WEF.
12 World Health Organization. (2002) Active Ageing: A Policy Framework. Available at: http:// whqlibdoc.who.int/hq/2002/who_nmh_nph_02.8.pdf
13 World Health Organization. (2007) Global Age-friendly Cities: A Guide. Available at: http:// whqlibdoc.who.int/publications/2007/9789241547307_eng.pdf
14 Christensen, K., Doblhammer, G., Rau, R. & Vaupel, J.W. (2009) Ageing populations: the challenges ahead. Lancet, 374, 1196-2008.
15 Olshansky, S.J. & Carnes, B.A. (in press) Zeno’s Paradox of Immortality.
16 Reither, E.N., Olshansky, S.J. & Yang, Y. (2011) Forecasting the Future of Health and Longevity. Health Affairs, 30(8),1562-1568.
17 Olshansky, S.J. et al. (2009) Aging in America in the Twenty-first Century: Demographic Forecasts from the MacArthur Research Network on an Aging Society. The Milbank Quarterly, 87(4), 842-862.
18 Crimmins, E. & Beltran-Sanchez, H. (2011) Trends in Mortality and Morbidity: Is there a compression of morbidity? Journal of Gerontology: Social Sciences, 66, 75-86. 19 Butler, R.N. et al. (2008) New model of health promotion and disease prevention for the 21st
century. British Medical Journal, 337, 149-150.
20 Kirkwood, T. (2008) A systematic look at an old problem. Nature, 451, 644-7.
21 Martin, G.M., Bergman, A. & Barzilai, N. (2007) Genetic determinants of human health span and life span: progress and new opportunities. PLoS Genet, 3, 125.
22 Miller, R. (2009) “Dividends” from research on aging: Can biogerontologists, at long last, find something useful to do? Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 64(2), 157-160.
23 Butler, R.N. et al. (2008) New model of health promotion and disease prevention for the 21st