Has human lifespan reached its maximum limit?

By Sally Robertson, B.Sc.Oct 6 2016

According to a study published in Nature, the maximum human lifespan is fixed, has already been reached and is not likely to increase as time goes on.

Scientists from the Albert Einstein College of Medicine have shown that improvements in survival tend to decline after people have reached 100 years and that the age reached by the oldest person in the world has not increased since the 1990s.

Driven by advances in areas such as public health, diet and the environment, the average human life expectancy has steadily and significantly increased since the 19^th century. Analysis of demographic data has shown a continuing reduction in old-age mortality and an increase in the maximum age at death. This, together with the fact that lifespan in other species has been found to be extendable through genetic or pharmaceutical intervention, has led scientists to question whether or not human longevity is strictly fixed by species-specific genetic constraints.

To investigate, Jan Vijg and colleagues looked at global mortality and population data from the Human Mortality Database, for more than 40 countries. They found that the number of people born in a particular year that survived to old age (70 years or more) increased with their calendar year of birth, indicating an ongoing rise in average life expectancy.

However, when the researchers assessed improvements in survival since 1900 among people aged 100 years or more, there was a peak in survival at around age 100, followed by a rapid decline, irrespective of the year of birth, suggesting a possible limit to human lifespan.

The researchers then analyzed maximum age at death using data from the International Database on Longevity. Across four countries, (the US, UK, France and Japan) they looked at people confirmed to have lived to 110 years or more between 1968 and 2006. This maximum age quickly increased between the 1970s and 1990s, but reached a plateau at around 1995, also indicating a limit to human lifespan. The team note that this plateau occurred close to the death of the oldest person ever reported, 122-year old Jeanne Calment, who died in 1997.

Vijg says that although some scientists have proposed that there is no reason to assume that the increase in maximum lifespan will end soon, the Einstein study strongly suggests that the maximum lifespan has been reached and that this occurred in the 1990s.

"Further progress against infectious and chronic diseases may continue boosting average life expectancy, but not maximum lifespan," he adds. "While it's conceivable that therapeutic breakthroughs might extend human longevity beyond the limits we've calculated, such advances would need to overwhelm the many genetic variants that appear to collectively determine the human lifespan. Perhaps resources now being spent to increase lifespan should instead go to lengthening health span--the duration of old age spent in good health."