Humans unlikely to ever live past 125 years, scientists claim
Published 06/10/2016 | 09:13
Humans are unlikely to live longer than 125 years old and even advances in medical sciences will not break through the barrier, a huge study has concluded.
Since the 19th century average life expectancy has risen almost continuously, with a baby born today expected to live until 81, compared to just 50 years in 1900.
The march of improvement in longevity led many scientists, such as Harvard’s Prof David Sinclair, to speculate that there is no upper limit on how long humans can live for.
But a new study suggests that the upward trajectory does have a ceiling, and we have already hit it.
Scientists at the Albert Einstein College of Medicine, in New York, believe that human life expectancy probably peaked in 1997 with the death of the world’s oldest woman Jeanne Calment, who died age 122.
In the last two decades, the age at which the oldest people die has largely plateaued around 110, and, despite astonishing scientific advance, nobody has beaten Calment’s record. The oldest person alive today is Emma Morano, 116, an Italian who was born in 1899 although an Indonesian man claims to be 145.
The researchers believe that imperfections in the copying of genes will always mean there is finite limit to human life. The claim that 125 years is the limit of human lifespan and the chance of a supercenterian passing that is just one in 10,000.
"Demographers as well as biologists have contended there is no reason to think that the ongoing increase in maximum lifespan will end soon," said senior author Dr Jan Vijg, professor of genetics at Albert Einstein.
“But our data strongly suggest that it has already been attained and that this happened in the 1990s.
"Further progress against infectious and chronic diseases may continue boosting average life expectancy, but not maximum lifespan.
"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 healthspan - the duration of old age spent in good health."
Dr Vijg and colleagues analysed information from the Human Mortality Database, which compiles mortality and population data from more than 40 countries.
Since 1900, the number of people surviving past 70-years-old has been increasing which has led to a surge in life expectancy. But when the researchers looked at survival improvements since 1900 for people aged 100 and above, they found that gains in survival peaked at around 100 and then declined rapidly, regardless of the year people were born.
The team then looked at data from Britain, the US, France and Japan from the International Database on Longevity, and focussed on those who lived till 110 or older.
Age at death for these supercentenarians increased rapidly between the 1970s and early 1990s but reached a plateau around 1995 at 110. This plateau, the researchers note, occurred close to the death of Calment in 1997.
The age that Calment died, 122, is very close to that predicted by the Hayflick Limit, which suggested that there was a finite number of times that a normal human cell population could divide before stopping.
In 1960 US anatomist Leonard Hayflick said that humans could not live beyond 120 based on the speed at which telomeres – the protective caps on the end of chromsomes deteriorate.
However Prof Sinclair, of Harvard University, who is renowned for saying there is no upper limit to human life, said that science was moving so quickly that it still may be able to live far longer.
“New technologies to enhance our body’s defences against aging have been made in labs throughout the world that could break through this apparent limit to human lifespan,” he said.
“In 1900, it would have been difficult to predict the impact of antibiotics.”
Prof David Melzer at the University of Exeter said the limit appeared ‘sensible.’
The new research was published in the journal Nature.