A Longer Walk Into the Sunset

Americans are living longer than ever before, but experts are split on whether the trend will continue--an issue that has important implications for how seniors and society plan for retirement.

In 2003, life expectancy in the United States hit an all-time high of 77.6 years, the Centers for Disease Control and Prevention announced last month. And many experts believe that life expectancy will climb even higher in the coming decades. But some argue that obesity and emerging diseases could put a halt to the rapid pace of longevity extension. The debate is more than just academic: The financial future of tomorrow's retirees is at stake.

Over the past century, life expectancy has increased at a rate of about two-and-a-half years per decade. An array of factors, including antibiotics, reductions in infant mortality, and improved treatments for heart disease have kept more of us living into old age. And "there's no evidence that we've begun to reach a limit of human life spans as of yet," says Richard Suzman, associate director of the National Institute on Aging in Bethesda, Maryland.

Perhaps there's no biological reason why we won't all live into the triple digits (see "Living to the Max"). But at least one researcher predicts that our lifestyle could reverse the trend toward expanding longevity. "Today's young people may actually live shorter and less healthy lives than their parents, and the reason is obesity," says S. Jay Olshansky of the University of Illinois, Chicago. He and his colleagues reached this conclusion after trawling through a population database and collecting numbers on body mass index (BMI), a ratio of weight to height. Knowing how BMI correlates with survival, and which BMI yields the lowest death rate, the researchers calculated how much longer the population could live if everyone who is obese slimmed down to an optimal weight. Their estimate, published last week in the New England Journal of Medicine: an additional 2 to 5 years. That number is on par with the life expectancy boost that would come from eliminating cancer entirely, says Olshansky: "Obesity is rivaling other fatal diseases."

Yet many predictions of future life expectancy don't take into account the magnitude of the obesity crisis, Olshansky says. He argues that most longevity forecasts merely extrapolate from historical data, and that demographers therefore miss what's going on in people alive today--the very population they're making predictions about. Obesity has risen fivefold in recent decades, and the crisis has hit children especially hard. But the consequences of America's ballooning weight problem have yet to be reflected in mortality numbers. If today's obese young people carry their heft into later life, demographers can expect an increase in deaths at middle age from obesity-related diseases such as diabetes, heart disease, and cancer, Olshansky says. Furthermore, an emerging infectious disease or flu pandemic could cut even more deeply into life expectancy, he says.

Demographer Samuel Preston of the University of Pennsylvania in Philadelphia calls Olshansky's predictions excessively gloomy. In an editorial accompanying Olshansky's paper, he predicts that further medical advances will fuel the trend of rising life expectancy. Obesity, he says, is just one of hundreds of factors that combine to determine life expectancy, and he contends that most predictions already factor it in.

Most demographers seem to side with Preston's rosier view. In a recent survey published in the North American Actuarial Journal, a majority of experts predicted that life expectancy will continue to rise at rates similar to those seen in the past several decades. If that pace continues, we could see a 25-year gain during the 21st century, says demographer Ronald Lee of the University of California, Berkeley. How the actual figures play out will influence how well Social Security and other retirement programs can meet retirees' needs.

Seventy years ago, when the Social Security system was formulated, a 65-year-old could expect to live another 12 or 13 years. Today, the average man might enjoy 16 years of retirement, with women looking at 20 years of retired life. "That's a very long time, and people will need large sums of money to support themselves," says Alicia Munnell, director of the Center for Retirement Research at Boston College. Many retirees might not have enough funds to support such a long retirement period. "Most retirees have about $30,000 in liquid assets, their home, plus Social Security," says Munnell. If current saving trends continue, many retirees will face a severe decline in their standard of living after they stop working, she says.

Social Security is already projected to confront shortfalls--although no one can agree on when--and Congress and the Bush Administration are at odds over how to shore it up. And Medicare is already in financial trouble. The problems both programs face could grow even worse if their beneficiaries continue to live longer. Although Social Security actuaries have figured increases in longevity in their projections, their life expectancy predictions remain lower than those currently made by the U.S. Census Bureau, says Suzman. If Social Security estimates turn out to be too conservative, the fund could drain even faster than anticipated. On the other hand, if obesity stalls life expectancy, the Social Security fund could remain in the black longer than expected.

If life expectancy climbs significantly--or if the government raises the retirement age--workers might need to extend their working lives so they spend more years contributing to Social Security and fewer years drawing from it. "The fact that jobs have become less physically demanding has raised the potential for people to stay in the workplace longer, doing jobs that require their minds instead of their bodies," says Munnell. Meanwhile, people in jobs that remain labor-intensive might choose to switch to jobs that are less physically demanding as they grow older. Last month, AARP launched an online service, called Workforce Initiative, designed to link its members age 50 or older with job openings at 13 prescreened companies. The program could encourage other companies to hire older workers, something many are currently reluctant to do. Of course, they might eventually be forced to do so by necessity, says Munnell. The retirement of baby boomers coupled with a decline in the number of youngsters ready to enter the workplace will shrink the labor force, which could make older workers more attractive to employers, says Munnell.

Although demographers express confidence about their longevity projections, their predictions apply to populations, not to individuals. People who want to live long, healthy lives--and enjoy decades of retirement--might try putting less food in their mouths and more funds in their retirement accounts.

Christie Aschwanden is a freelance writer who has promised herself she will deposit money into her retirement account, just as soon as she gets through tax time.