Pushing the boundaries for human life?
A good article from HeralToday about the future health of the US population but also about the puzzling measures and dynamics of life expectancy and mortality.
Life expectancy is on the rise and mortality is on the decline; indeed the boundaries of the ceiling of life expectancy and the floor for mortality are creating much grey hair on many a scholar's head. But what about this (new) theory; will obesity reverese this trend?
'Longer life. Less disease. Less disability. The trends have continued for more than a century as humans have become bigger, stronger and healthier.
But can they - will they - continue? Or is there some countertrend, obesity or an overuse of medications, perhaps, that will turn the statistics around?
Researchers say, for now there are no easy answers, only lessons in humility as, over and over again in recent years, scientists have seen their best predictions unfulfilled.
Life expectancy, for example, has been a real surprise, says Eileen M. Crimmins, a professor of gerontology and demographic research at the University of Southern California. "When I came of age as a professional, 25 years ago, basically the idea was three score years and 10 is what you get," Crimmins said. Life span was "this rock, and you can't touch it."
"But," she added, "then we started noticing that in fact mortality is plummeting."
Will it continue much longer?
"It is an extremely controversial area, and the answer is, We don't know," said Dr. Richard J. Hodes, director of the National Institute on Aging.
Some worry, for example, that today's fat children will grow up to be tomorrow's heart disease and diabetes patients, destroying the nation's gains in health and well-being.
The mixed picture has led to disparate views about what is likely to occur.
S. Jay Olshansky, a professor of epidemiology and biostatistics at the University of Illinois at Chicago, predicted in The New England Journal of Medicine that obesity would lead to so much diabetes and heart disease that life expectancy would "level off or even decline within the first half of this century."
Olshansky was countered by Samuel H. Preston, a professor of demography at the University of Pennsylvania. Preston cited the population's overall better health, from childhood on, and said that obesity had already been factored into national projections of life spans and that the projections were that life spans would continue to increase.'