How long could we live? Live well, that is.

"There is no brick wall." So speaketh the noted demographer and biogerontologist Jay Olshansky, referring to the fact that humans have no “death genes”, nor “aging genes” that regulate the process of making you old. He was speaking at the 2009 Age Boom Academy at the International Longevity Center, tp which director Bob Butler was kind enough to welcome me back as an alumna. Some other compelling facts from Olshansky’s talk, which was titled “The Demographic Perspective on Longevity”:

• Following puberty, the risk of death doubles every seven years. This exponential rise is a biological attribute of our species, and many others.  Longer lifespan does not change the trajectory.
• The 30-year increase in the human lifespan in the 20th century is explained by the fact that we’ve redistributed death from the young to the old. Time removes the high-risk people. (That’s why biologists and geneticists are so interested in centenarians and supercentenarians — people over 110.)
• As life expectancy raises, it becomes more and more difficult to increase it further.  This is a mathematical certainty. (Olshansky warned of the dangers of making linear extrapolations from biological phenomena, with the example that by 2420 humans will be running a one-minute mile, at which point men will weigh 293 lbs and women 261.)
• The biology of death today is far more predictable than it was in 1900. Thanks to clean water and antibiotics, TB and diarrheal diseases have given way to heart disease, cancer and stroke. If we find a cure for those, we’ll die from something else.

 

While we should still go after the big diseases, their remediation may make us older longer — the worst of all possible outcomes. “The goal is to live healthier.  If we live longer that is a bonus,” Olshansky declared. Like a great many of his colleagues, he’s making the case for intervening in the aging process itself, for attacking the major killers simultaneously, through the window of aging. We already invest in the extension of healthy life in young people; where’s the justification for withholding it from the old? “Slowing aging will do what no drug or surgery can ever do: extend your years of youthful vitality and simultaneously postpone all the costs, disability, and lethal conditions expressed at later ages,” he said.

 

Postpone, not prevent. “The operative word is delay,” the demographer cautioned. Remember that exponential increase every seven years? If we can delay the onset of aging by seven years, eliminating one doubling interval, the risk of frailty and disability would be halved for all future generations. Ah, math, so crisp, so clear. The predominant one-disease-at-a-time paradigm may buy us additional life without health, but Olshansky optimistically concluded, “There’s wonderful ongoing science leading us in the right direction.”

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