Living to 100 Is Getting Easier
Living to be 100 years old just isn’t what it used to be. As of July, 1994, there were 50,000 centenarians in the United States, according to the U.S. Census Bureau’s latest resident population estimate.
That’s a huge increase from a decade earlier, when the Census Bureau reported 22,000 centenarians, up from 15,000 in 1980.
“We know the numbers are increasing very rapidly,” says John Wilmoth, an assistant professor of demography at UC Berkeley’s Center for the Economics and Demography of Aging, who tracks worldwide changes in the longevity of elderly populations. Recently he discussed aging trends and their implications.
Question: Why do some people live to be incredibly old?
Answer: There hasn’t been a thorough analysis of why people survive to extreme old age, but some people who have spent a lot of time observing very old people have suggested that a strong-willed, determined character is a common feature of their personalities. Centenarians tend to be very determined and independent. They have sturdy personalities. They’re unflappable, bullheaded--they’re going to do things their way. Nothing really gets to them. Also, these are people who have very little history of illness--they just tend to be very resistant to illness. Genetics plays a role. And you have to throw in luck.
Q: What is the life expectancy right now in the United States?
A: In 1900, life expectancy was 49 years; today it’s 76. It’s a long-term trend that’s been going on for a few hundred years. Going back 500 years or more, people had a life expectancy of 25 years. That’s because a quarter to a third of the population would die in the first year of life, so that brought the average way down.
Today the age range of death is more concentrated--almost everybody dies in their 70s and 80s. The effects of aging have taken over. People are dying of some fundamental deterioration of the body (as opposed to childhood illness and infectious diseases). . . . Medicine began having an impact in the ‘30s and ‘40s. Before that, people were almost better off to avoid the doctor.
Q: Will life expectancy continue to increase?
A: Now we’re at a point where further increases in life expectancy will probably be much slower. They will come by slowing down the rate of physical deterioration and pushing back the time at which people become ill with some fatal degenerative disease like cancer. There will be continued slow increases in average longevity and in record longevity, but probably not enormous improvements.
Q: Why do women live longer?
A: We really don’t know, but it’s very real. In every country, at every age, women have a greater chance of living than men. (In the United States), the average life expectancy at birth for men is 72 and 79 for women. In Japan, it’s approaching 82 years for women and about 76 years for men.
Q: Is there a limit to the human life span?
A: There’s no real sign of a limit, but at the same time we shouldn’t expect herculean improvements in life expectancy in the short term. We’ll continue to inch up slowly. Within our lifetime we should not expect to see 130-year-olds, but we will definitely see more people between 100 and 110. Of course, anything is possible. There could be enormous breakthroughs in our understanding of human genetics.
Q: Do some experts believe there is a limit to the human life span?
A: Yes. The classic argument is that this limit has not changed throughout most of history. A common number has been 110 or 120. But there really is no basis for that.
Q: Why do you think there’s no limit?
A: One piece of evidence is that we have documented a long-term increase in the number of centenarians in industrialized countries and long-term increases in the maximum age at death. Take Sweden, for instance. We have very accurate data for a period of over a century. The maximum age at which a person dies in a given year has been going up steadily for at least the last 130 years--an increase of one year every two decades, five years every century. It’s gone from around 101 to around 109.
Q: Do you expect this trend to continue?
A: It could. It’s very difficult to predict what’s going to happen. . . . When you see a clear linear trend, one can reasonably assume it will likely continue for at least another 20 or 30 years, but beyond that I wouldn’t bet my lunch money.
Q: In terms of life expectancy, how do Americans stack up against the rest of the world?
A: We’re not even in the top 10, for either men or women.
Q: Why not?
A: In the United States, the leading causes of death are heart disease, cancer, stroke and accidents; in Japan--which has the highest life expectancy of any major country and lowest infant mortality--it’s cancer, not heart disease. It has to do with our diet. There’s no doubt the Japanese have a diet that’s lower in fat and higher in carbohydrate than we do.
It also has to do with social and economic inequality. In Japan, almost everyone is well taken care of from a very young age. There’s an ill-defined group of people in this country who are substantially less advantaged socially and economically, and that disadvantage shows up in their mortality status.
Q: You mentioned that once Americans get to be old that they seem to live longer than the elderly in other countries. Why is that?
A: There is some evidence that once we get to 85, Americans may be better off. But we don’t know for sure if the numbers are accurate. The most plausible explanation is that the money we spend for the elderly may really be buying something--longer life. . . .
But the expensive heroic procedures to keep the elderly alive raises questions. Is it really buying a high quality of life? Or is it prolonging their lives in a state that really isn’t enjoyable?
There’s a larger question of whether this is a proper investment of scarce resources. The ratio of what U.S. governments at all levels spend on social services and medical services for one elderly person compared to one child is about 4 to 1. In many other industrialized countries, it’s more like 2.5 to 1. Given that infant mortality in this country is more than 50% higher than in Japan, it’s questionable whether having lower mortality later in life is admirable. In some respect, it might be reflecting a trade-off in life. We may be doing well by the elderly but not so well by children.
