The Oldest Old

As many nations of the world experience aging populations, attention is increasingly turning to changes within the older population itself, especially changes in the age structure of this older population. As a general statement, over time the elderly population is likely to become older; such a phenomenon is important because there are likely to be important differences among age groups within the older population, such as health status and economic well-being.

The aging of the older population occurs primarily because of reductions in death rates, which in many countries have become concentrated in the older ages. In the United States, for example, life expectancy at birth increased by more than 50 percent during the twentieth century; not surprisingly, most of the increase was due to reduced mortality among children and the elderly. However, almost all of the declines in mortality among children occurred prior to 1950, while declining mortality for the elderly occurred much more recently, during the final decades of the twentieth century. Thus, while population aging (the number or share of the population that has reached some specified birthday, usually, the sixtieth or sixty-fifth) is mostly due to reductions in fertility, the aging of the older population and the rising number and share of the "oldest old" (conventionally those at least eighty-five years of age) is mostly due to reductions in old-age mortality.

To illustrate the dynamics of the oldest old population, consider census data from the United States, which first became available for this age group beginning in 1910. That census enumerated 167,500 very old Americans who accounted for about two of every thousand of the nation's 92 million persons and only 4 percent of the 3.9 million Americans aged sixty-five or older. By mid-century, there were 578,000 Americans who had reached their eighty-fifth birthday. Their share of total population, while still very small, was about twice what it had been in 1910. Current estimates of the very old population of the United States suggest nearly 4.3 million individuals or about fifteen of every thousand Americans. In the past half century, the number of oldest old Americans has risen more than seven fold while the national population has not even doubled. Forecasts by the U.S. Bureau of the Census for the next fifty years suggest 19.4 million very old Americans by 2050, nearly 5 percent of the projected national total (see Figure 1).

Gerontologists are particularly interested in these demographic trends because the oldest old have historically differed from the more general older population in many important respects. While it is not possible to state with any certainty that this pattern of differences will continue in the future, there are several interrelated issues that must be taken into account when contemplating the social and economic consequences of the demographic shifts summarized above.