HUMANS HAVE NOT HIT MAXIMUM LIFESPAN YET, STUDY SAYS.
Researcher says we could live to 150 or beyond
Jeanne Calment liked cream cakes, a nightly glass of port and, when she was 110, acquired a taste for those strong, dark and lethally chic French cigarettes, Gauloises.
Calment, the oldest documented person who ever lived, died in 1997 at age 122.
So l ast October, when Albert Einstein College of Medicine researchers concluded Calment was a statistical outlier, and that the biological limit to the human lifespan is peaking at around 115.
“From now on, this is it. Humans will never get older than 115,” Jan Vijg, an Einstein expert on aging, told The New York Times.
Now, however, two Canadian biologists, in a critical comment published in Nature, argue the Einstein supercentenarian analysis was flawed and there’s no evidence the maximum human lifespan has reached a plateau.
“We just don’t know what the age limit might be,” McGill experimental biologist Siegfried Hekimi said in a statement. “In fact, by extending trend lines, we can show that maximum and average lifespans could continue to increase far into the foreseeable future.”
Hekimi, a 60-year-old professor of biology and former professional cyclist ( Tour de France in 1982), works with worms and mice.
His lab has shown that, by making a single change in the smallest piece of DNA of nematode worms, the animals can live five times longer, work that could one day open the door to interventions to slow our own biological rate of aging.
Hekimi believes it’s not out of the realm of possibility humans could live to 150, or beyond. Longer life, he adds, doesn’t necessarily mean extra years of poor health. Observational studies of centenarians show that people aren’t “hanging in, staying alive, despite disease,” he said in an interview. “They just didn’t get sick.
“Whether it was luck or their genotype, that can be debated. But the fact is, mostly the people who live a very long time, they were always healthy. They didn’t have heart disease or diabetes.”
Almost unavoidably, he said, an increased lifespan means a l onger, healthy lifespan. ( Though virtually blind and hard of hearing, and apart from mild heart failure and rheumatism, Calment had reportedly been in good health a month before she died.)
When the Einstein study was published in October, putting the biological limit to human life at 115 years, “it was obvious to me this was a weak analysis,” Hekimi said.
The Einstein group analyzed data from people verified as living to age 110 or older between 1968 and 2006 in the four countries — the U. S., France, Japan and the U. K. — with the largest number of the longest-lived.
The age of death of the supercentenarians increased rapidly between the 1970s and early 1990s, but reached a plateau, they reported, around 1995.
They c oncluded t hat people who reach t heir 110th birthday today have no greater life expectancy than those who lived to 110 in the 1970s, and that the age of death of the world’s oldest person hasn’t increased since Calment died in 1997.
“Further progress against infectious and chronic disease may continue boosting average life expectancy,” Vijg said when the study was released, “but not maximum lifespan.”
But when they analyzed the same data, Hekimi and co- author Bryan Hughes questioned why the Einstein team split the data into two groups: one before a certain arbitrary date and one after.
Without dividing the data set in two, the McGill duo found a long-term increasing trend in maximum life, with no evidence of plateauing. Theirs is one of five critiques of the original paper.
Since Confederation in 1867, Canadians’ life expectancy has more than doubled to 82 ( 80 for men, 84 for women).
Hekimi says it stands to reason maximum lifespan will follow the same trend, meaning there’s no indication that, while average lifespan goes up, maximum lifespan won’t go up in parallel.
“If this trend continues and our life expectancy of the average person becomes 100, t he l ongest person might make it to 150,” he said. “Probably not you or me. But maybe our grandchildren and great-grandchildren.”
The Einstein researchers, in a response, said they remain confident in their results.
While there may be no detectable limit yet to how long people can live, it doesn’t mean there’s a limitless lifespan.
The 2016 Canadian census counted 8,230 centenarians, a 41 per cent increase over 2011 figures.
“So, people are moving into age 100, but we have no idea where that will end,” said Parminder Raina, scientific director of the McMaster Institute for Research on Aging. “Will these people continue to live longer and longer, or is there a certain limit to life expectancy? I think it’s an open scientific debate.”
The ol dest Canadian supercentenarian alive today is Ellen “Dolly” Gibb, of North Bay, Ont., who turned 112 in April.
LIFESPANS COULD CONTINUE TO INCREASE FAR INTO THE FORESEEABLE FUTURE.