A century ago, most Americans lived to be about 50. Today people over 100 make up the fastest-growing segment of the population. As some researchers bet that children born today will live to be 150, others say there is no
upward limit on longevity By Karen Wright Photography by Mary Ellen Mark DISCOVER Vol. 24 No. 11 | November 2003 | Biology & Medicine
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A few years back, biodemographer Jay Olshansky called his friend Steve
Austad, a gerontologist, after reading an outrageous quote attributed to
Austad about aging. Olshansky, at the University of Illinois, and Austad,
at the University of Idaho, have long shared an interest in the human life
span. But they differ on some points. Austad had been quoted as saying
that someone alive today could survive to the unprecedented age of 150.
“You don’t really mean that,” Olshansky told his friend.
“Oh yes, I do,” Austad replied. In fact, he would bet on it. Before long
he and Olshansky had agreed to put $150 each into an investment fund, to
be distributed to the relatives of the winner in 2150. They agreed that,
in order for Austad’s progeny to collect, the 150-year-old has to be in
reasonably good health and that proof of the person’s age has to be
impeccable. By adding $10 each every year, they figure that by 2150, the
$300 fund will grow to be worth $500 million.
Austad isn’t worried about his kin collecting: “We’ve made phenomenal
progress in understanding aging in other animals in the last 10 years. I
can’t believe we won’t make improvements in [human] antiaging treatments
in the next hundred.”
Most students of human longevity agree that exercise, antioxidants,
low-fat diets, and prostate exams will join forces with a battery of new
techniques to extend the lives of seniors and improve their quality of
life. But that amiable projection raises a tough question: If medical
science were to eliminate geriatric infirmity and disease entirely, how
long would the human body last? Is there some built-in expiration date for
each member of our species beyond which no one will ever survive? If so,
what is it, and why does it exist?
Demographics of the last two centuries seem to be on the side of soaring
life spans. Worldwide, average life expectancy has increased from about 27
years to more than 65. In the United States, a person born in 1900 lived,
on average, less than 50 years; now the average life span is 78. Japanese
women, the longest-lived people ever known, now have a life expectancy of
85 at birth.
These unprecedented gains are reflected in the number of people surviving
to extreme ages. The longest-lived human whose age has been unequivocally
documented is Jeanne Louise Calment, a Frenchwoman who died six years ago
at age 122. Although people of such advanced age are still rare, they’re
becoming more commonplace by the minute. The United States now boasts a
population of more than 40,000 people aged 100 and older. In 1950 there
were only 2,300 centenarians in this country. James Vaupel of the Max
Planck Institute for Demographic Research in Rostock, Germany, says the
number of centenarians in many industrialized nations is doubling every
decade.
Vaupel has shown that the maximum life expectancy among such countries has
risen steadily by more than two years each decade since 1840. The increase
is “so extraordinarily linear that it may be the most remarkable
regularity of mass endeavor ever observed,” Vaupel wrote in a 2002 paper
coauthored by Jim Oeppen of Cambridge University. If that pace continues,
Vaupel maintains, the average life span in industrialized countries in
2150 will be 122.5, making 150-year-olds common.
Demographer Ronald Lee of the University of California at Berkeley says
Vaupel’s analysis came as “a big surprise. We just did not expect to see a
linear increase in life expectancy. It’s hard to resist extrapolating that
line. That’s a 25-year gain every century.”
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