A new study suggests that Jeanne Louise Calment, a French woman who died in 1997 at the age of 122, is unlikely to have her title as the oldest human who ever lived usurped any time soon. 

Researchers with the Albert Einstein College of Medicine in New York have found the human lifespan has likely reached its natural limit, which is stuck at around 115 years.

“The chances are very high that we [have] really reached our maximum allotted lifespan for the first time,” said Jan Vijg, co-author of the research.

It has been surmised by prominent scientists in recent years that the first person to reach the age of 1,000 is likely alive today, but this new study suggests that’s very unlikely.

In the journal Nature, the researchers describe how record analysis from various international databases indicates there is a ceiling to the human lifespan, and we have already hit it. Looking at data for 41 countries and territories from the Human Mortality Database, the researchers found that the rate of improvements in survival differ greatly between levels of old age. While large gains are seen for ages 70 and up, the rate of improvement drops rapidly for ages 100 or more.

“[For] the oldest old people, we are still not very good at reducing their mortality rates,” said Vijg.

Moreover, in 88 percent of the countries, the ages showing the greatest rate of improvement have not changed since 1980.

The researchers also looked at the International Database on Longevity and analysed data from France, UK, the US and Japan – countries that have a high proportion of “supercentenarians” (those aged 110 or above.) They found that the maximum reported age at death rapidly increased between 1970 and the early 1990s, rising by roughly 0.15 years every year. In the mid-to-late 90s, however, a plateau was reached, with the annual maximum reported age at death at around 115 years.

Researchers claim this apparent limit to human lifespan is a byproduct of a range of genetic programming that controls processes like growth and development.

“Based on the data we have now, the chance that you will ever see a person of 125 [years] in a given year is about 1 in 10,000,” said Vijg.

The news is even worse for men who want to live as long as they can. According to the Wikipedia entry on the world's longest-living people, only six of the Top 100 are men.

h/t The Guardian, Nature.