Intended for healthcare professionals

Education And Debate

Population aging and health

BMJ 1997; 315 doi: (Published 25 October 1997) Cite this as: BMJ 1997;315:1082
  1. Robert N Butler, chief executive officera (robert.butler{at}
  1. a International Longevity Center (US), Mount Sinai Medical Center, New York, NY 10029, USA

    Trends in population aging

    People in industrialised nations are living longer than ever before. In this century alone, average life expectancy from birth has increased by more than 25 years, and nearly five of those 25 years has been added to average life expectancy from base age 65. Indeed, the most rapidly growing age group comprises those aged 80 and above, and in some countries people over the age of 100 are leading the way in the rate of population growth by age. In most parts of the world women tend to live longer than men—nearly seven years longer in industrialised nations. In addition, reports from Japan, the United States, and Europe show that people are living not only longer but more healthily. In the United States, for example, the rate of disability has decreased noticeably despite population aging (fig 1).

    Fig 1
    Fig 1

    Number of chronically disabled Americans aged 65 and over, 1982-96 (total number of Americans aged 65 and over was 26.9 million in 1982, 30.8 million in 1989, 33.7 million in 1994, and 34.1 million in 1996). Reproduced with permission of Proceedings of the National Academy of Sciences of the United States of America from Manton et al1

    Unfortunately, the developing world has not enjoyed the same revolutionary increase in longevity. None the less, 60% of people aged 60 and older live in developing countries—which have huge populations—and this percentage is expected to rise to 80% towards the middle of the next century. The marked inequalities in life expectancy between the developed and developing worlds, as well as discrepancies in life expectancies within particular nations, correlate with inequalities of wealth and income, and these in turn are associated with how much or how little education and access to health care the populations have. Many countries already have at least 10% of their populations aged 65 and older (1). Figure 2 shows the rapidity of the projected percentage increase in the population aged 65 and older in the developing world. Figure 3 details the dramatic growth of the population aged 80 and over. As it is in this population that disabilities and dementias increase markedly, this figure illustrates the dramatic impact of population aging on health care.

    Countries with at least 10% of population aged 65 and over in 1994 (adapted from Hobbs F et al2)

    View this table:

    Western societies with declining birth rates are approaching the point where older people will soon outnumber children. This unprecedented trend in population aging has profound effects on society and its institutions, such as the state of the economy, delivery and use of health services, pension systems, family life, medical research agendas, end of life decision making, private and public resource allocation, and living arrangements. One especially critical concern is the perceived role of population aging in driving up “unsustainable” health costs, although so far technology is the main cause of rising health expenditures.

    Summary points

    People in all parts of the world, and particularly in industrialised nations, are living longer than ever before

    This unprecedented population aging trend has profound effects on society and its institutions, including health care

    Biomedical research and better healthcare measures, as well as other factors, have enabled people to live longer and reduced disability rates

    Increased life expectancy, however, brings new challenges, including longer lifetime exposure to toxic agents and greater demands on healthcare systems and social entitlements

    Individuals, society, government, and the research community all have a responsibility to meet these challenges and improve the quality of life

    Fig 2
    Fig 2

    Projected percentage increase in populations aged 65 and over, 1994-2020. Adapted from Hobbs et al1

    Impact of health on population aging

    The age structure of any society's population depends on birth rates, death rates, and net migration in or out of the society. Population aging was first the result of declining birth rates and was first noticed in France in the 1830s. But by the 20th century population aging was widespread in industrialised nations because of both lower death rates and lower birth rates. Lower death rates were due in part to an increase in people's consumption of calories. It has been estimated, for example, that in preindustrial France as many as one third of the population had inadequate caloric intake. One of the consequences of the industrial revolution was the increased availability of food, followed by increased stature and greater longevity. In addition, there is synergy between inadequate nutrition and higher susceptibility to infection. With higher caloric consumption, the incidence of infection declined. Infectious diseases were reduced still further with modern sanitation and the increased availability of immunisations, antitoxins, immune sera, and, later, antibiotics.

    Gradually the early cruelties of industrial factory life, such as overcrowded living conditions and the resulting spread of infectious diseases, began to decline. Material existence began to improve with the growth of the middle class in Europe, North America, and Japan. The availability of pension funds, access to health care, and medical research further increased average life expectancy. By the 1970s the earlier marked reductions in maternal, childhood, and infant mortality were joined by reductions of up to 50% of deaths from heart disease and stroke. Both disease driven and basic biomedical research, including the biology of aging, continue to reduce disability and mortality. Hip replacements, angiotensin converting enzyme inhibitors, and intraocular implants illustrate the practical applications of such research. Moreover, the decline in disability rates along with the availability of social entitlements have improved the quality of life. None the less the extent of frailty and dementia accompanying population aging continues to prompt concern over quality of life issues and healthcare expenditures associated with late life.

    Fig 3
    Fig 3

    Percentage of population aged 80 and over, 1994 and 2020. Adapted from Hobbs et al1

    Impact of population aging on health

    Clearly, advances in health have promoted population aging. However, the reverse—the impact of population aging on health—is more difficult to describe. With population aging came the possibility of a longer lifetime exposure to various potential toxic agents, either recognised or unrecognised. This is particularly true of tobacco and food substances such as fats. Tobacco contributes to heart disease and stroke as well as cancer of the lung and chronic pulmonary disease. The modern high fat diet has been associated with heart disease and certain cancers, such as colon cancer and possibly breast cancer. Other aspects of lifestyle, too, over time, have an impact on health. Lack of exercise leading to physical deconditioning contributes to the chronic diseases of late life. Osteoporosis or bone thinning, sarcopenia or muscle thinning, and inadequate cardiac conditioning, for example, all follow from a lifetime of inadequate physical fitness. Indirectly, population aging could also have adverse effects on the health of populations in general if society does not allocate resources effectively and fairly along the life span, to ensure that children and older people receive the resources they need. Surprisingly, there is not a proportionate relation between the percentage of older people and the percentage of gross domestic product devoted to health care, according to Binstock (figures 4 and 5). Administrative costs, profits, the healthcare delivery system, and society's commitment to health care are among the factors that partially account for this discrepancy.

    Fig 4
    Fig 4

    Selected nations ranked by percentage of population aged 65 years and older, compared with percentage gross domestic product spent on health care, 1990. Reproduced with permission of Binstock3

    Fig 5
    Fig 5

    Selected nations ranked by percentage of population aged 80 and older, compared with percentage of gross domestic product spent on health care, 1989. Reproduced with permission of Binstock3

    Despite population aging, however, healthcare policymakers in various nations have not generally constructed ideal systems of geriatric medicine and long term care (only Britain has a well developed specialty in geriatrics), and much remains to be done. Links between acute and long term care services—the two pillars of comprehensive geriatrics—need to be made. While families are the primary caregivers, their capacities to be caregivers to older people have changed in response to modern conditions such as the entry of women—the traditional caregivers—into the workforce. Therefore, expansion of hospital services, nursing homes, and community based services, as well as assisted living housing—for example, blocks of flats with meal and other services for frail and disabled residents—are recognised in most industrial countries as being necessary adaptations to population aging.

    One common goal of long term care programmes in industrialised countries is the prevention of impoverishment. A major exception is the United States, where the only available public funding is part of public assistance for the poor (Medicaid). About half of bills for nursing home costs and an even greater proportion of bills for the cost of home care are paid privately and without insurance, whereas some other industrialised nations have publicly supported programmes of social and personal care—for example, respite care, home help, adult day care—and services are allocated according to individual need, not ability to pay. Sweden has one of the most systematic approaches to long term care, with a range of services for elderly people, including nursing homes and housing.

    Different nations have tackled the financing of long term care in different ways. In Germany public long term care insurance predominates, whereas in Britain commercial long term care insurance has burgeoned. In Australia, long term care is provided mostly by the private sector (profit and non-profit organisations), and includes retirement villages, hostels, and nursing homes operated by voluntary agencies and private corporations, with state governments providing a smaller portion of services. In contrast, in 1990 the Japanese government announced a 10 year “golden plan” for the welfare of elderly people and in 1997 legislated on a public long term care insurance plan modelled on Germany's.

    Taking responsibility for population aging

    Sustaining a growing older population is the responsibility of everyone—from the government, to the private sector, to individuals themselves. As people are living longer they clearly must plan to take better care of themselves throughout life. They must prepare financially by saving and investing more and working longer. They must also take some responsibility for their health by adopting healthy habits early in life and maintaining them throughout life. Strong relations seem to exist between having goals and structure in life and a person's health, longevity, and higher quality of life. Societies will be able to sustain longer life expectancies and population aging better if people not only prepare for their old age but are encouraged by society to remain productive through paid work or voluntary activities.

    Government and the private sector should assume more responsibility in assuring less disability in late life by making greater investments in medical research. The benefits of medical research for older age groups will derive principally from efforts to reduce frailty and dementia, which today are people's greatest fears about old age. Once Alzheimer's disease and the other dementias are preventable or treatable, the negative imagery associated with individual and population aging will be dramatically reduced. For countries to respond effectively to population aging, they must make further investments in geriatrics and biomedical research. This necessitates systematic reforms in healthcare delivery as well as disease prevention and health promotion efforts and a reversal in the current trend of cutting research budgets.


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