|Jay Olshansky: Hitting a dead end|
Will people live ever longer and longer? Will life expectancy keep pushing towards 100 and beyond?
No chance, says Jay Olshanksy, a demographer specializing in longevity, who today upended for me this widely held notion.
Olshanksy, a professor at the University of Illinois at Chicago's School of Public Health, was speaking to journalists at the Age Boom Academy –a gathering of aging experts pulled together by Columbia University’s Graduate School of Journalism and its Mailman School of Public health.
Worse yet, he believes that life expectancy is about to reverse course. Japan, he said, is on the verge of decline. And the same could be true of other Western countries.
How is this possible?
“Every generation,” he explained, “carries its own set of mortality and morbidity risks.” We should not forecast the future based on the longevity we’re seeing now.
He cites research out of the United Kingdom that found that people born between 1925 and 1934, who grew up during the difficult years of Depression and World War II, are living longer than those born before them –and after them.
Why? It’s not known but one theory, he said, is that this group, known as the “golden cohort,” experienced “caloric restriction” during critical years in their youth. Food rationing might have extended their lifespans, much as some dietary experiments with mice have done. (A study of long-lived Okinawans offered a similar explanation.)
Olshanksy guesses that the generations of obese children that followed carry a different, and likely shorter, life expectancy. “The obesity epidemic that swept the globe will carry those effects for generations,” he predicted, citing his 2005 study.
Another reason humanity might well have reached a lifespan limit is because we’ve found ways to push back age-related diseases such as heart disease and cancer. That leaves us face to face with what kills us all in the end – “senescence” – the body’s natural aging process.
“We’ve reached a point of limited returns,” Olshansky said. 'We may have reached the biological limitations of our bodies."
But living longer should not necessarily be the goal. Rather than “life extension,” science, medicine and public policy should be working toward “health extension” –- trying to increase the number of years that we live in good health before the grim reaper does us all in.