Heath and Aging

Why Population Aging Matters: A Global Perspective

Trend 3: Rising Numbers of the Oldest Old

An important feature of population aging is the progressive aging of the older population itself. Over time, more older people survive to even more advanced ages. For research and policy purposes, it is useful to distinguish between the old and the oldest old, often defined as people age 85 and over. Because of chronic disease, the oldest old have the highest population levels of disability that require long-term care. They consume public resources disproportionately as well.

The growth of the oldest old has a number of implications:

  • Pensions and retirement income will need to cover a longer period of life.
  • Health care costs will rise even if disability rates decline somewhat.
  • Intergenerational relationships will take on an added dimension as the number of grandparents and great-grandparents increase.
  • The number of centenarians will grow significantly for the first time in history. This will likely yield clues about individual and societal aging that redefine the concept of oldest old.

The oldest old constitute 7 percent of the world’s 65-and-over population: 10 percent in more developed countries and 5 percent in less developed countries. More than half of the world’s oldest old live in six countries: China, the United States, India, Japan, Germany, and Russia. In many countries, the oldest old are now the fastest growing portion of the total population. On a global level, the 85-and-over population is projected to increase 151 percent between 2005 and 2030, compared to a 104-percent increase for the population age 65 and over and a 21-percent increase for the population under age 65 (Figure 5). Past population projections often underestimated decreases in mortality rates among the oldest old; therefore, the number of tomorrow’s oldest old may be significantly higher than anticipated.

The percentage of oldest old will vary considerably from country to country. In the United States, for example, the oldest old accounted for 14 percent of all older people in 2005. By 2030, this percentage is unlikely to change because the aging baby boom generation will continue to enter the ranks of the 65-and-over population. In Europe, some countries will experience a sustained rise in their share of oldest old while others will see an increase during the next two decades and then a subsequent decline. The most striking increase will occur in Japan: By 2030, nearly 24 percent of all older Japanese are expected to be at least 85 years old. Most less developed countries should experience modest long-term increases in their 85-and-over population.

As life expectancy increases and the oldest old increase in number, four-generation families become more common. The aging of the baby boom generation, for example, is likely to produce a great-grandparent boom. As a result, some working adults will feel the financial and emotional pressures of supporting both their children and older parents and possibly grandparents simultaneously.

While people of extreme old age—that is, centenarians—constitute a small portion of the total population in most countries, their numbers are growing. The estimated number of people age 100 and over has doubled each decade since 1950 in more developed countries. In addition, the global number of centenarians is projected to more than quintuple between 2005 and 2030 (Figure 5). Some researchers estimate that, over the course of human history, the odds of living from birth to age 100 may have risen from 1 in 20 million to 1 in 50 for females in low-mortality nations such as Japan and Sweden.

FIGURE 5: PROJECTED INCREASE IN GLOBAL POPULATION BETWEEN 2005 AND 2030, BY AGE (bar graph)
Age Increase
0-64 21%
65+ 104%
85+ 151%
100+ 400+%

Source: United Nations Department of Economic and Social Affairs, Population Division. World Population Prospects. The 2004 Revision. New York: United Nations, 2005.

Publication Date: September 2011
Page Last Updated: October 7, 2011