How long can humans live? It's an age-old question but one that may now be obsolete as there appears to be no upper limit to life expectancy in sight. That’s according to an international team of age researchers, who have for the first time gathered a database of the oldest people in the world - those who lived beyond their 110th birthday.
This new scientific data shows that records are being broken every year. Today, there is not only a dramatically increasing number of centenarians, but also more and more men and women who live to 110 years or older.
Age researchers in 15 nations have spent the last ten years scouting their countries for people who reached the extremes of old age. Together they found over 600 genuine supercentenarians in the USA, Canada, Japan, Australia, France, Italy, Spain, Germany, Switzerland, Belgium, the United Kingdom and in the Nordic countries. Of the 600, nearly 20 lived beyond 115 and - no real surprises here - the vast majority (almost 90 percent) were women.
Although Ireland was not one of the countries investigated, a UK researcher identified an Irish woman as one of the first carefully validated supercentenarians - Katherine Plunket, the oldest person in Irish history. She was born on November 20, 1820, and died on October 14, 1932, at the age of 111. She therefore became a supercentenarian in 1930, which is “very early for the appearance of a genuine supercentenarian in any country,” the researchers declared.
While searching for these ”supercentenarians“ and trying to find accurate documentation of their age, the researchers not only collected data for scientific purposes, but also documented the fascinating personal histories and wisdom of those who lived more than a century. They have now published their findings and the stories of many of their subjects in the book “Supercentenarians” which was coordinated by the Max Planck Institute for Demographic Research (MPIDR) in Rostock, Germany.
“Investigating very old age has always been difficult for demographers," says Heiner Maier from the MPIDR. "Science has been plagued by myths and fairy tales."
He explains that most claims of modern-day Methuselahs appear promising at first glance, but usually turn out to be unverifiable. Entries in the Guinness Book of World Records aren't reliable either; their validation is often based solely on documents provided by the families of those who reached an advanced age and are not independently confirmed by scientists.
“A fundamental question in aging research concerns the trajectory of mortality at the highest ages. Until recently it was uncertain whether human mortality after age 110 is slowly increasing, level, slowly decreasing, or rapidly decreasing,” Heiner, who is Dean of the Max Planck School, tells Scope.
“This uncertainty arose because reliable data on mortality after age 110 had not yet been collected. Almost a decade ago, an international group of researchers decided to establish a database that would allow the best possible description of the mortality trajectory beyond the age of 110.”
Specifically, the objective of this concerted effort was to gather complete lists of validated supercentenarians in as many countries as possible. The new data was used to create the International Database on Longevity (IDL, http://www.supercentenarians.org), which contains exhaustive information on validated cases of supercentenarians and permits unbiased estimates of mortality after age 110.
"The IDL is the first reliable record of scientifically verified data about supercentenarians on an international scope. It is the best existing account of mortality beyond the age of 110."
Heiner describes their main finding as remarkable: human mortality levels off at a probability of death of 50 percent per year after age 110. It appears the older we get, the more our mortality increase slows down. One study even raises the possibility that mortality may fall after age 115.
“Life expectancy is lengthening almost linearly in most developed countries, with no sign of deceleration. Extrapolating these trends would suggest that life expectancy will continue to increase in future years,” Heiner remarks.
However, he adds that, even though life expectancy at birth is steadily increasing, it is unlikely that we will see dramatic increases in maximum age in the near future – “barring major breakthroughs”.
Finding the supercentenarians was an unusual task for the demographers, as they could not rely on standard statistical methods. As most countries didn't have a central birth register in the late 19th century, when the supercentenarians were born, the scientists faced significant challenges to prove their age and often had to search through a massive amount of certificates, census lists, death registers and the paper files of universities and health and security administrations to identify supercentenarians.
The findings varied between countries. In the United States, 341 supercententarians were eventually verified (309 women and 32 men), whereas, in the much smaller country of Denmark, only two women were verified as being over 110.
Some researchers got lucky. In Germany, for instance, the researchers found a much faster method - they asked the Office of the German President for help. The President keeps a directory of residents older than 100, in order to send birthday congratulations. With the list in hand the researchers easily tracked down 17 supercentenarians.
The record holder in longevity is still the French woman, Jeanne Calment, who died in 1997 at the age of 122. The book "Supercentenarians" celebrates her life - how she met the painter Vincent van Gogh when she was 13 and how she took up fencing at age 87. She allowed herself one glass of port and one cigarette a day, and she enjoyed good food and wine, including cakes and chocolate, which she ate every day.
Apparently, Jeanne smoked until she was 117. The only reason she quit is because she got tired of asking people to light her cigarettes for her. She couldn't see well enough to do it herself.
When the demographers James Vaupel and Bernard Jeune, two of the authors of "Supercentenarians", visited her at age 120, she remarked that the most important thing in her long life was that "I had fun. I am having fun”.
Chris Mortensen's long life is also detailed in the book. Born in Denmark, he died at 115 in the United States. Currently the record holder as the world's oldest living man, at his advanced age he still enjoyed smoked cigars.
The Dutch woman Hendrikje van Andel-Schipper also reached the remarkable age of 115. Despite being born prematurely with a weight of only three pounds, she nevertheless avoided major life-threatening diseases until her nineties, when she was diagnosed with a breast cancer, and ultimately died of stomach cancer.
The African American woman Bettie Wilson, who died at the age of 115, even survived gall bladder surgery at age 114. And Elizabeth Bolden, also an African American woman, who was deeply religious and had ten great-great-great grandchildren, was allegedly completely mentally fit and was able to recount all the major details of her life on her 112th birthday.
“I was struck by the finding that there is apparently no secret of longevity,” says Heiner. “Supercentenarians appear to be almost as diverse as individuals at younger ages, albeit almost all are women, most enjoyed comparatively good health until advanced old age and none were heavy cigarette smokers. The number who did not marry or who had fewer children than average appears high compared with marriage and childbearing patterns for people who died younger,” he adds.
What is striking, he notes, is that many of the super old avoided dementia, at least until shortly before they died. This provides evidence that dementia is not an inevitable corollary even of extreme old age. Now researchers want to expand the use of the IDL and its data to investigate mortality at advanced age and the reasons for an extra long life.
In one of the book’s chapters, researchers Bernard Jeune et al, report that while the super old retained their youthful personalities and were able to live on their memories, none of them could escape the effects of extreme old age.
“Their physical functions declined markedly, especially after their 105th birthdays. They walked very slowly and had increasing difficulty in performing daily tasks. Their sight and hearing weakened, so that in the last years of their lives they were virtually blind and very hard of hearing. They spent their last years confined to wheelchairs and slept most of the time,” the authors wrote.
However, it was observed that, despite their advancing frailty, they did not fear death, and they appeared to be reconciled to the fact that they were approaching the end of life.
“They never expressed any wish to recover their youth. 'Enjoying and living are two different things,' as Chris Mortensen put it."
Heiner reiterates that the key to longevity is still elusive. So far the only thing for certain is that being a woman is clearly advantageous, since 90 percent of those celebrating their 115th birthday were women. Having ancestors who lived exceptionally long played as little a role as economic background, and half of the supercentenarians had no children. It is unclear, however, whether this evidence will remain constant with future supercentenarians. The search for the secret of super old age has only just begun.
The Irish supercentenarian
Katherine Plunket was 102 when she contracted bronchitis – her only serious health problem in her remarkable 115 years. Until then, she actively oversaw the upkeep of the home and gardens of Ballymascanlon House near Dundalk, one of her distinguished family's ancestral homes.
The longest-lived person in Ireland (1820 – 1932), Katherine was a member of the Anglo-Irish aristocracy. Her grandfather was a Lord Chancellor of Ireland. Her father became a Bishop and inherited the title of Baron Plunket.
She never married, but Katherine and her sisters travelled widely and visited almost every capital in Europe. She also made many sketches of flowers in France, Italy, Spain, Germany, and Ireland, which were bound in a volume and were presented in 1903 to the Royal College of Science. The collection is now in the Irish National Botanic Gardens at Glasnevin.
Katherine was included in the first ever Guinness Book of Records in 1955 and was also the last living person who had met Sir Walter Scott, when he stayed at her grandfather’s house in while she was visiting.
She credited her longevity to a carefree aspect of life.
Can we live forever?
|Aubrey de Grey|
Cambridge University geneticist, Aubrey de Grey, drew jeers of disbelief from many of his peers when he declared: “The first person to live to be 1,000 years old is certainly alive today; indeed, he or she may be about to turn 60. Whether they realise it or not, barring accidents and suicide, most people now 40 years or younger can expect to live for centuries.”
Aubrey may be wildly optimistic but he is not alone in the search for a virtual fountain of youth. In fact, a growing number of scientists, doctors, geneticists and nanotech experts - many with impeccable academic credentials - are insisting that there is no hard reason why ageing can’t be dramatically slowed or prevented altogether.
Scientists have been successful in prolonging the life of some animals. On a near-starvation diet rodents can live up to 40 percent longer, once they have the required vitamins and minerals. In addition, some of the genes related to ageing have been identified. Modifying these genes can lengthen the life of yeast, worms, mice and fruit flies. Yet, would these longer-living or slower-ageing animals prosper in the real world? Evolutionary theory predicts that longevity would come at a cost. Many of these mutants have been infertile.
But Robert Freitas at the Institute for Molecular Manufacturing, a non-profit, nanotech group in Palo Alto, California, is up-beat: “It will take time and, if you put it in terms of the big developments of modern technology, say the telephone, we are still about 10 years off from Alexander Graham Bell shouting to his assistant through that first device. Still, in the near future, say the next two to four decades, the disease of ageing will be cured.”
People are living longer and healthier - now what?
People in developed nations are living in good health as much as a decade longer than their parents did, not because aging has been slowed or reversed, but because they are staying healthy to a more advanced age.
"We're living longer because people are reaching old age in better health," said demographer James Vaupel, author of a review article which was published in the March 25 edition of Nature. The better health in older age stems from public health efforts to improve living conditions and prevent disease, and from improved medical interventions,
Over the past 170 years, in the countries with the highest life expectancies, the average life span has grown at a rate of 2.5 years per decade, or about 6 hours per day.
"It is possible, if we continue to make progress in reducing mortality, that most children born since the year 2000 will live to see their 100th birthday in the 22nd century," says James, who heads Duke University's Center on the Demography of Aging in the US, and holds academic appointments at the Max Planck Institute for Demographic Research in Rostock, Germany, and the institute of Public Health at the University of Southern Demark.
He ponders that it may be time to rethink how we structure our lives. "If young people realize they might live past 100 and be in good shape to 90 or 95, it might make more sense to mix education, work and child-rearing across more years of life instead of devoting the first two decades exclusively to education, the next three or four decades to career and parenting, and the last four solely to leisure."