February 21, 2015 | News | Supercentenarians
Jeanne Calment - a puzzle of longevity
140 years ago, on February 21, 1875, Jeanne Calment was born in the town of Arles, southern France. She died in 1997 at the ripe age of 122, with the longest confirmed human lifespan at record. Why she lived that long is a puzzle to researchers.
When Jeanne Calment entered the world on February 21, 1875, in the small French town of Arles, perpetual emperor Napoléon Bonaparte had been disposed just 5 years ago and the Third French Republic was still very young. Bismarck ruled in Germany and Jeanne Calment had to get to the age of 11 until Carl Benz sauntered Mannheim’s streets with the first automobile ever powered by an internal combustion engine.
At the grand age of 122 years and 164 days, she has been the longest-lived human on earth – by far. She lived three years longer than the next oldest, US-American Sarah Knauss, and five years longer than third-placed Lucy Hannah, also from the USA.
Scientists use the term “supercentenarians” to describe people aged 110 and above, such as Jeanne Calment. Research on modern day Methuselahs is still relatively young and the circle of scientists studying them still small as there are simply not that many ancients around yet. But the situation is changing rapidly. Life expectancy has been rising continuously, and with it the number of those who have lived well over a century. Fifty years ago, the age of 100 was still regarded a biblical age. Today, 110 and 115 year-olds show us that it is possible to live to an extreme old age.
Researchers are occupied by questions such as: Is there a genetic component to extreme longevity? Or can it be credited to personal lifestyle? Are there countries or regions of exceptional longevity? What does mortality look like at old age – is it rising linearly or exponentially? Surprisingly, first results indicate that mortality levels off at oldest old age, reaching a plateau, i.e., mortality is flat at a probability of death of 50 percent.
To address these questions, researchers need to do a lot of tedious work in preparation as they need to find out which of the supercentenarians stand validation. And this is not always a trivial task: Official documents that register birth must have already been available at the time the supercentenarian was born, and these documents must have survived through the century. “But most countries around the world do not have these kinds of documents. And with the countries that have them, you have to find the tricks and knack of getting access to the data,” says Heiner Maier, a supercentenarian researcher at the MPIDR.
He and another 35 colleagues from 15 countries got together to gather and validate data on the super-aged. The data sets they have to work with are different in each county, and the sources are not always reliable. “Experience has shown that ─ of all things ─ the large official data sets on the highest age groups are extremely prone to errors,” Heiner Maier explains. Researchers in the USA, for example, used the data of the public pension insurance scheme. But when they matched the data against the central death register, they noticed large differences. “It happens at times that data on people who had already died accidentally are not taken off the official statistics. Such mistakes are often only noticed when that person is shown to have reached an absurdly high age,” says MPIDR-researcher Heiner Maier.
In Germany, the researchers received their first data set from the Office of the Federal President. The local authorities in Germany are required to advise the Federal President of any person celebrating birthday at high age so that the Head of State can send birthday congratulations. When the researchers began their search in 2005, they received 1400 names from the Federal Presidential Office. They then had to check each name against records in the Residence Registry Offices. Of the total, around 950 people remained where the researchers could safely say that these were indeed aged 105 or above at that time, among them 17 supercentenarians.
But these days it gets really exciting: “Because life expectancy is rising rapidly, I am sure that today we have many more supercentenarians among us than 10 years ago,” says Heiner Maier. “Now is just the perfect time to continue the research.”
The data sets would be larger then, and this would enable researchers to address some of the questions still open. They would be able to analyze how mortality has changed over the life course, for example, and whether there are so-called hotspots of longevity, i.e., places where people live to a very high age.
But the researchers will not be able to address the question of what kind of lifestyle is conducive to exceptional longevity as the data they have is not linked to individual information on health. “Scientifically speaking, this is unfortunate, but when looking at it from data protection, it is to be welcomed,” says Heiner Maier.
A book published by the consortium of researchers provides some indications as to what helps to live long. The researchers had visited 20 individuals aged 116 or above around the world, asking them and relatives questions about their lifestyle, character traits, and state of health. The methuselahs all had in common that they generally never smoked or just smoked a little, they were not overweight and they only had few children. Often, their relatives described them to be strong persons with a strong will to live.
Jeanne Calment is the only one who does not fit in. She had smoked almost all of her life, that is, up to her 119th birthday. Researchers continue to chew over her high age. Since 25 years now she has been holding the world record of having been the oldest person ever. Madame Calment outlived the second-oldest person by three years and the third-oldest person by five years. Now, outliers are common in statistics, but a difference as large as that can hardly be explained by statistics. “We don’t have an explanation yet why this large difference has arisen,” Heiner Maier concludes.