Centenarians are the fastest growing segment of our population. The second fastest is the age group 85 .
Currently, there are about 40,000 centenarians in the United States, or a little more than 1 centenarian per 10,000 in the population; 85% of them are women, 15% are men.
The Boom in Centenarians: From Pyramid to Rectangle.
The age composition of the population is changing dramatically. More and more people are now able to achieve their individual life expectancy potentials. This is a dramatic change from the turn of the 20th century, when many people died prematurely especially in infancy and the average life expectancy was 46 years. Families on average would lose a quarter of their children to infectious diseases.
When current centenarians were young children, the population, in terms of age, was in the shape of a pyramid, with the vast proportion being young and only a very few reaching very old age. With the advent of clean water supplies and other public health measures, much of this high childhood mortality disappeared resulting in an average life expectancy of 64 years by 1960. Then with marked improvements in medical prevention and intervention for diseases that befall adults, such as hypertension, diabetes, heart failure and coronary artery disease, and numerous cancers we have seen the average life expectancy climb even higher to age 78 years. Now, the shape of the population is very different. We are experiencing a rectangularization where more and more people are living beyond the vulnerable childhood years and achieving old age, so that the number of older people nearly equals the number of children.
A tremendous force in the population will drive the unprecedented growth of the 65 population -the baby boomers. The first baby boomers recently turned 50 years old. Actually, this 70 million-strong group now constitutes the "elder boomer" generation! By the first decade of the next century, there will be as many seniors as there are people under the age of 20. Approximately 3 million of these elder boomers can expect to become centenarians. An important component of the elder boomers’ ability to achieve extreme age is their relatively high level of education, income and attention to good health habits.
Are Centenarians a New Phenomenon?
Life span is the maximum age obtainable for the species and it is defined by the age of the oldest living individual. In the case of humans, that individual was Madame Jeanne Calment who died at the age of 122 years in August, 1997. Madame Calment therefore had a tremendous responsibility … in her later years, every day she lived, she extended the human life span by a day.
Prior to the twentieth century, though life expectancy was about half of what it is today, life span was probably not that different. There are numerous instances of people living well into their nineties reported as far back as the sixteenth century. Titian, the well known Italian master painter, lived to at least age 90 and may have been as old as 99 years of age. Hippocrates reportedly died in his mid eighties. To say that life span also doubled in even the last thousand years would be hard to substantiate, especially from an evolutionary point of view. For example, what genetic changes could possibly occur over the course of a thousand years that would provide such an enormous survival advantage?
