Linda Geddes in Nature:
Jeanne Calment outlived her daughter and grandson by decades, finally succumbing to natural causes at the ripe old age of 122. Calment, who was French and died almost two decades ago, is thought to be world's longest living person. But if subsequent advances in medicine have lulled you into thinking that you might exceed this record, think again. An analysis of global demographic data published in Nature1 suggests that humans have a fixed shelf life, and that the odds of someone beating Calment’s record are low — although some scientists question this interpretation. They say that the data used in the analysis is not unequivocal, and that the paper doesn’t account for future advances in medicine.
Human life expectancy has steadily increased since the nineteenth century. Reports of supercentenarians — people such as Calment who live to older than 110 — together with observations of model animals whose lifespans can be extended through genetic or dietary modifications, have prompted some to suggest that there is no upper limit on human lifespan. Others say that the steady increase in life expectancy and maximum human lifespan seen during the last century will eventually stop. To investigate, Jan Vijg, a geneticist at Albert Einstein College of Medicine in New York City and his colleagues turned to the Human Mortality Database, which spans 38 countries and is jointly run by US and German demographers. They reasoned that if there’s no upper limit on lifespan, then the biggest increase in survival should be experienced by ever-older age groups as the years pass and medicine improves. Instead, they found that the age with the greatest improvement in survival got steadily higher since the early 20th century, but then started to plateau at about 99 in 1980. (The age has since increased by a very small amount).