- The number of people living past 100 years of age is increasing.
- The scientific community is divided on the topic of the continually increasing maximum human life span.
- Statistical modeling shows that a life span of 130 years is a possibility by 2100.
Human life span significantly impacts society. An
Researchers at the University of Washington recently published a study in the journal Demographic Research, which shows a likely rise in human longevity by the end of this century.
While the number of people who live past the age of 100 has grown to half a million worldwide over the last several years, there are a few who are living to be 110 or even older. Those who have passed the 110-year mark are referred to as supercentenarians.
Jeanne Calment of France is the oldest
The recent study concludes that longevity, such as Calment’s, may continue to rise slowly by the end of this century. Statistical modeling examining the extremes of human life shows that a life span of 130 years may be attained.
Many scientists and researchers disagree on the plasticity of old-age mortality. Some forecast a fixed limit to human life span, based on biological forces, such as the inevitable
Others note that mortality for people in their 80s and 90s has decreased significantly in recent years. They also argue that proposed caps to human life span have always been broken within an average of 5 years after they were suggested.
What both these arguments have in common is uncertainty. Unknown future scientific breakthroughs, and a lack of knowledge regarding the mechanisms of aging, prevent forming definitive conclusions about human life span.
“People are fascinated by the extremes of humanity, whether it’s going to the moon, how fast someone can run in the Olympics, or even how long someone can live,” said Michael Pearce, a doctoral student and lead author of the longevity study. “With this work, we quantify how likely we believe it is that some individual will reach various extreme ages this century.”
Before 2010, statistical analysis of supercentenarians was limited by age attainment bias, which is the tendency of people of advanced age to exaggerate or round up their age.
To reduce the risk of this possible bias, the authors used updated longevity data in the International Database on Longevity (IDL), established by the Max Planck Institute for Demographic Research in Rostock, Germany.
This database was the first dataset that rigorously verified birth, life, and death records of supercentenarians and that only included those whose age could be confirmed with a high degree of certainty.
For the purpose of this study, the researchers used the IDL records of 1,119 individuals in 10 European countries and in Canada, Japan, and the United States who reached at least 110 years of age.
The database also includes records of nearly 14,000 individuals from these countries — except Finland, Japan, Spain, and Sweden — who died between the ages of 105 and 109, called semi-supercentenarians.
The authors used a Bayesian conditional probability statistics methodology. This methodology describes the probability of an outcome based on knowledge of existing conditions that might influence the event in question.
Using Bayesian population projections, the researchers could probabilistically forecast the number of people who may survive to age 110 during this century.
They created projections for the maximum reported age at death in all 13 countries for the years 2020–2100. Their results show a nearly 100% probability that someone will break the current maximum-age-of-death record set by Calment.
There is also a 99% probability of a person living up to 124 years and a 68% probability of reaching 127 years. An even longer life span of 130 years is possible but much less probable — at 13%. The data also indicate that someone reaching the age of 135 years is extremely unlikely, with a probability of just 0.4%.
The authors point out that even with population growth and advances in healthcare, the mortality rate will continue to flatten after a certain age. For example, someone who lives to be 110 has about the same probability of living another year as someone who lives to 114.
Co-author Adrian E. Raftery explained further by saying that once people reach the age of 110 years, they still die at the same rate.
Even though the model used in this study suggests that the maximum reported age at death will continue to increase, the frequency at which this record is broken will decrease unless the number of supercentenarians grows significantly. With a continually expanding global population, researchers believe this growth is a possibility.
“This is a very select group of very robust people,” said Raftery. “They’ve gotten past all the various things life throws at you, such as disease. They die for reasons that are somewhat independent of what affects younger people.”