Last year a high-profile article was published in the journal Nature, looking at longevity or life-spans of humans. The researchers found that 115 years was the maximum that people could live up to. Beyond this, the body functions would decline and end.
A new study by McGill University biologists has now been published in Nature claiming that there is no evidence for such an upper age limit.
According to experts, human lifespan is not limitless but it is too early to accept that there is a limit to maximum human age and it is quantifiable with a number. Life beyond 115 years may be a reality. It does not have to end there.
Siegfried Hekimi, Professor of Genetics at McGill University in Canada and one of the lead authors of the new study explained that when most people live till the age of 50, one who lived till 80 was considered to be lucky or genetically blessed. So now if the average life span is 80-90 years, those very persons who were lucky or genetically blessed would live up to 110 or 120. This means that if the life spans are expanding, the upper limit is also on the rise. Thus 115 is a number that cannot limit this scientifically.
Average lifespan has risen as recently as the 1990s. In the 1990s the average lifespan was around 50 years in the United States. Average life span of babies born now is around 79 years – a nearly 30 years increase!
Further, some years have a higher number of oldest lived persons dying taking the average lifespan higher compared to other years. This accounts for a considerable variation in the average lifespan.
For example, some years the oldest person to die could be 100 or 110 pulling up the national average lifespan. Some years the oldest person to die could be 90 years bringing down the average life span. Hekimi explained that this was like the throw of a dice and over many throws there is a lot of spread of values.
In the original paper published in October 2016, the scientists divided their population into two groups – those between 1968 to 1994 and 1995 to 2006. They looked at individuals aged over 110 years in four countries: the UK, US, France and Japan.
They noted that maximum lifespan rose in the first era followed by a plateau or flattening in the second era. But during this time Jeanne Calment, the oldest-lived human, was alive and she passed away in 1997 at the age of 122 years.
This pulled up the maximum lifespan considerably and the findings could be wholly attributed to Calment, Hekimi says. Based on this the earlier data could be a misinterpretation say researchers.
References
Inside the Alzheimer's Association: Dr. Heather Snyder on Driving Research and Collaboration