Jeanne Louise Calment on her 121st birthday, shortly before she died. Calment is still the oldest person that we know of that has ever lived. Credit: Wikimedia Commons

When Jeanne Louise Calment died in 1997 she did so at the venerable age of 122 years. Her family grieved but the rest of the world looked to the future with hopeful eyes since Calment, the oldest person at the time ever at the time of her death, was a symbol for rising human longevity. People started to say at the time “Well if a person ca live to 122 then a couple decades from now we can expect people to live 130 maybe 150 years.” But almost 20 years later, Calment is still the oldest human. The second oldest people died at 119 and 117, respectively, and right now the oldest living person is 116. Despite considerable advances in medicine and living standards, we seem to have reached a longevity ceiling and a new study has the data to back this claim.

Don’t make plans past 115

Researchers at the Albert Einstein College of Medicine, New York, systematically scoured all the demographic data they could find from the last century. Their research suggests there’s a biological limit to how long people can live and estimates suggests this ceiling sits at around 115 years of age. Calment or Emma Morano, the current oldest person in the world, are exceptions to the rule.

The team specifically looked at demographics from the United States, France, Japan and the United Kingdom since these four countries have the most supercentenarians — people over 100 years of age.

According to the researchers, in the 1970s the maximum age was 110. Then in the 1990s it was 115 but 20 years later there wasn’t any meaningful improvement in longevity. In other words, we seem to have reached a plateau.

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From a statistical point of view, the odds of at least one person in the world living past his 125th birthday is less than 1 in 10,000, as reported in the journal Nature. That’s pretty slim and explains why there are some deviations from the rule, like Calment.

The 115 ceiling is probably rooted in our biology and can be explained from an evolutionary standpoint. The primary reason why we age and what ultimately causes death from natural causes is DNA damage. Every time a cell divides, telomeres — structures that keep chromosome ends from fraying and sticking to each other sort of like shoelace tips — get shorter. When they get too short, the cell can no longer divide; it becomes inactive or “senescent” or it dies. This shortening process is associated with aging, cancer, and a higher risk of death. So telomeres also have been compared with a bomb fuse.

That’s why around age 80 or 90, many develop diseases like cancer or Alzheimer’s. But there’s a weird quirk. If you make it past 90, the odds of developing such diseases actually goes down, not up. We don’t know why for sure yet but some speculate that rare genetic makeup helps the venerable old advance in age towards supercentenarian status.

Then there’s the problem that evolution favors the young, who can reproduce and carry their genes, not the old. As such, genetic changes that threaten our existence are rarer at a young age and more common at old age, simply because the old are more expendable. It sounds ruthless but that’s how life works. The old must make room for new blood.

Things like antibiotics, vaccines, cancer therapies have not only raised the survival rate of the young but extended our lifespan as well. The average lifespan has increased by twenty years since the dawn of the last century, and in some parts of the world by thirty. But there seems to be a ceiling. Then again, the world’s oldest people today were born around 1900 — a time when most of the medical procedures we take for granted today didn’t even exist. We also have, arguably speaking, better diets than 100 years ago. So some speculate that those that will reach 150 years of age were born yesterday, in a manner of speaking.

So far, the data says otherwise, and we might have to wait a long time to know for sure. If there’s truly a biological limit to how long we can live, then our only chance to augment longevity is through some sort of gene therapy. The future’s double centenarians might be designer babies, for instance.