June 4, 2002
By Nancy Volkers
InteliHealth News Service
Comedian Woody Allen once said, "You can live to be a hundred if you give up all the things that make you want to live to be a hundred."
According to a recent analysis, many more of us may live that long in the not-too-distant future.
Since 1840, life expectancy in industrialized nations has been increasing by about 2.5 years per decade, and no end to the increase is in sight, according to researchers in a recent issue of Science.
While they admit that immortality will never happen, the researchers — Jim Oeppen of Cambridge University, and James Vaupel of Duke University and the Max Planck Institute — write that if the trend continues, life expectancy will reach 100 by about 2060.
Not so, says Kenneth Minaker, M.D., associate professor of medicine at Harvard Medical School and chief of the Geriatric Medicine Unit at Massachusetts General Hospital.
"I don't agree, and I don't think most gerontologists would agree," he said. "What is certainly clear is that life expectancy has gone up dramatically, but it's very unclear that lifespan is changing at all."
Life expectancy is the number of years, usually calculated from birth, says Dr. Minaker, at which 50 percent of babies born will have died. For example, in 2000 the U.S. Centers for Disease Control and Prevention estimated that life expectancy in the United States was about 77 years. That means that in 2077, one of every two people born in 2000 is expected still to be alive.
Lifespan, on the other hand, is the maximum age to which anyone could be expected to live. Human lifespan, Dr. Minaker says, appears to be set right around 100 years.
"There are a few statistical outliers," he says — people who buck the trend, like France's Jeanne Calment, who lived to be 122 before dying in 1997 — but "lifespan for humans does appear to be fixed."
The reason is unclear, although there are two major theories. One is that years of wear and tear simply become too much and overwhelm the system. The other states that aging is programmed into our DNA like the color of our eyes.
Worldwide, life expectancy is about 70 years for women and 65 for men. The highest life expectancy — for Japanese women — is 85 years.
According to Dr. Minaker, most biologists and mathematicians think that human life expectancy will eventually reach about 85 years in the United States, but won't go much beyond that.
From his point of view, quality of life is more important than quantity. "What medicine is all about is not getting everyone to age 100, but getting people to whatever age they're going to get to as healthily as we can," he says.
And what of the incredible increases in life expectancy? A 92-year-old patient of Dr. Minaker's — sounding remarkably like Yogi Berra — had this to say:
"It's too bad the extra years we gain are at the end of our life."
