File photo of elderly couples viewing the ocean and waves along the beach in La Jolla

File photo of elderly couples viewing the ocean and waves along the beach in La Jolla (Mike Blake, Reuters)

And what about obesity? It's still not completely clear.

By 2040, obesity will reduce life expectancy by 0.733 percent for men, and 0.677 percent for women, according to Preston. Those are trends that he believes will be offset by other gains as people stop smoking.

Richard Suzman, director of behavioral and social research at the National Institutes of Health's National Institute on Aging, puts it this way: "Obesity is a little more complicated."

So far among boomers serious weight gain appears linked to rising disability and all the costs associated with that, but because of modern medicine's ability to treat complications like diabetes and heart disease, the impact on longevity is there, just not as much, he says.

Additionally, some experts say obesity's true impact on longevity won't be seen until current youth get older since they are more likely to have been obese as children than today's elders.

And Chris Ruhm, a professor of public policy and economics at the University of Virginia, sees another shoe ready to drop: severe obesity. He expects high rates of obesity to be a drag on life expectancy and severe or morbid obesity, even in the baby boom generation, to be a much bigger problem.


Even pessimists like Olshansky do not believe that all or even most baby boomers will die at younger ages than their forbears. But he sees a future in which the rate of improvement slows overall and some groups - boomers who are from lower socio-economic strata and are black or Latino - see actual declines.

"Rich people live significantly longer than poor people do," says John Bailey Jones, an associate professor of economics at the University of Albany, State University of New York. In the United States, the wealthy live nearly five years longer on average than do the most destitute, according to Denney's research.

NIH's Suzman sees a "very uneven" picture when it comes to U.S. mortality: "It's a combination of public health, lifestyle and medical treatments, and there are still very large gaps."

Furthermore, people facing economic stress seem to die younger than those who are comfortable, and job loss worries could push more boomers into that low-income, high-stress group with higher death rates than their well-to-do peers, suggests Rice University's Denney.

Many people in developed countries overseas outlive Americans.

Overall those in Japan, Singapore, Canada and even beleaguered Italy and Spain live longer than those in the United States, which ranked 50th in latest CIA World Factbook. Even with that gap, it's important to note that other countries fund their retirement plans differently and face unique distributions of age and wealth.


In April, the Social Security board of trustees predicted that the funds that finance the retirement, disability and survivors programs will be exhausted in 2035. At that point, benefits would need to be cut or new funds found. Over the next 75 years, the shortfall in the Old Age, Survivors and Disability (OASDI) fund would amount to 2.67 percent of U.S. payroll.

This projection has triggered much political infighting over whether the United States should be cutting Social Security benefits or raising taxes to pay for them.

But those calculations are based on the expectation that the constant improvements in mortality (fewer deaths at every age) would continue unabated. The trustees project mortality declining by roughly 0.77 percent a year for every year going forward as far as the eye can see.

"We're simply projecting that improvements will occur at roughly the same... (rate) as in the past," Stephen Goss, chief actuary for the Social Security Administration, told Reuters.

The agency's math relies on this assumption: the average 65-year-old in 2020 can be expected to live 19.4 more years if a man and 21.3 more years if a woman. By 2030, when the last baby boomer turns 66, the average 65-year-old woman could expect to live to 87.9 and the average 65-year-old man would live to 86.

What if the trustees are wrong? If mortality rates stopped improving, and remained constant over the next 75 years, that would cut the OASDI actuarial deficit by about 0.45 percent of payroll, about one sixth of the projected shortfall over the next 75 years, a Social Security spokesperson told Reuters. That won't completely save the trust fund from shortfalls, but it would help.

Medicare is trickier to assess, Goss and other experts say.

"The net effect (of slower longevity improvements) might not be large," agrees Ronald Lee, director of University of California, Berkeley's Center for the Demography and Economics of Aging. "There will be fewer elderly people to provide health care for... (but) those elderly people who are alive will be less healthy and have higher healthcare needs."

Some insurance companies selling annuities -- firms like Metlife Inc, Prudential Financial Inc, New York Life Insurance Co and TIAA CREF -- could also benefit.

For individuals planning their futures any surprising shifts in life expectancy really wouldn't change their course. Some children of boomers could inherit money earlier than expected.

Still, retirees will have to manage their money expecting it to last 25, 30 or even 40 years, because no individual could count on being one of the unlucky few dying younger. Keith Moon and John Entwistle - two of the four original The Who band members - did indeed die before they got old. But the others -Pete Townshend and Roger Daltrey - are still going strong.

(Editing by Lauren Young and Alden Bentley)