Common sense suggests that as humans age, the risk of death caused by simply getting older gets higher. While that might be true till about 80, the risk of death by old age actually starts to slow down as people get really old. Researchers have found that once people reach the age of 105, the risk just plateaus out.
A new study carried out by a team of biologists aimed to study and explore one of humanity's most fundamental, existential queries – Is there a maximum lifespan for humans that cannot be breached? Such a limit, if it exists, is yet to be reached, says lead author Elisabetta Barbi who along with her team went on to study about 4,000 Italian people.
Ageing is a topic that has been through much debate through most of human history and beating old age is something that has remained a fantasy. The idea that mortality rates get higher as people age to extremes or level out after a point where "the likelihood of dying stays close to constant for those at the relevant age", and beyond is what the study wanted to find out.
Previous studies have not been conclusive with regards to this question of whether human mortality plateaus after a certain age, say the researchers. In fact, they quoted studies that showed that there are chances of mortality plateauing as well as increasing.
However, in this study, the team's findings strongly suggest that the older people get, their mortality rates plateau. Barbi and her team have found this evidence in what they are calling the "oldest-old". Between 2009 and 2015, careful data taken from verified sources of Italians who lived over the age of 105 were taken up. Survival trajectories of 3,836 people were used for the study and the data, the researchers claim, was used to estimate deaths with "unmatched precision and accuracy, free from the typical issues that have limited earlier extreme-age demographic studies."
Results of the study point out that death rates increase exponentially with age, but begin to slow down after 80, and they completely plateau out after 105. Also, for those over 105, the mortality rate declines slightly across different groups of people born within the same year and this strongly suggests that human longevity is actually increasing over time.
The research paper was first published in the journal Science.