The recent upsurge of interest in geriatrics and gerontology throughout the Western world, in the Soviet bloc countries and also in Japan, is not based only on the larger presence of the elderly and their better articulated demands. It is also based on the expectation that this proportion of elderly will always be with us and, indeed, will continue to increase. Let us see whether the expectation that geriatrics and gerontology are a growth industry is well founded. The population projections for the United States, Current Population Reports Series P25 No. 952 issued by the Census Bureau in June 1984, are a good case in point. The United States’ demographic processes are similar to many other urban-industrial countries’; and it has great cultural and technological influence on other urban-industrial countries in the setting of demographic trends. Moreover, the new American projections are extraordinarily elaborate and relatively clearly explained.

Let us examine the fundamentals of the United States projections in relation to the processes tending to make for faster or slower demographic ageing. In doing so, we can find some of the answers to the general question: Where do old people come from? and more pointedly: Why do they come up the population pyramid in larger or smaller numbers in different periods? Figure 1 shows the successive re-shaping of the American population pyramid as it has grown progressively older; and also shows its future age composition according to the medium population projection which foresees further increases in the proportion of people aged 65 and over.