In the 1850s, the average life expectancy in the US at birth was only 40 years old. Now, the average American can expect to live until at least 78. Recent medical research has teased us with the promise of extending human life further. But, what are the implications of this new medicine and what consequences would it have upon society?
Films, such as Logan’s Run and Soylent Green, have painted grim visions of an overpopulated future, where drastic measures are taken to control these overcrowded worlds and their scarce resources. The need for strict population control is not pure fantasy – until recently, China had the One-Child Policy, due to their booming population in the 1970s.
One might think that a longer-living society would lead to an increase in population, but the reality is quite different. Population growth is more determined by birth rates than mortality rates. “In the very short term, falls in mortality do create population growth,” observes Jane Falkingham, professor and director of the Centre of Population Change at the University of Southampton. “In the longer period, it is fertility that is the engine rather than mortality.”
- Ageing: the girls who never grow old
- The amazing fertility of the older mind
- The secret to a long and healthy life? Eat less
Recent clinical trials in mice have shown diabetic animals given the drug metformin, first introduced in 1957, are living longer than non-diabetics, who did not take the drug. And it’s been suggested that metformin could protect against basic ageing itself, and not just type 2 diabetes.
However, there are some possible pharmaceutical treatments that may not only protect against ageing, but actually reverse the effects of ageing itself.
Despite massive advances in health science, there is still a limit to how long the human body can go on (Credit: Alamy)
The almost vampiric practice of elderly people being given blood transfusions from young donors has been discovered to have some medical credibility. This fascination with blood’s potentially life-giving properties was first pursued by the German doctor Andreas Libavius in 1615, where he considered connecting the arteries of an older man to that of a young man.
Libavius was confident it would succeed, and results from experiments in 2005 showed the idea had promise. Old mice became healthier with young blood, whilst the young mice, who were infused with blood from elderly mice, did much worse. However, the risks associated with blood transfusions, such as lung injury and infections, should not be overlooked.
Yet, there are treatments being developed that are not as controversial and are repeatedly being proven as effective in laboratory tests.
By targeting these cells, ageing could not only be delayed, but also, to a degree at least, reversed – Peter de Keizer
Mice that have their senescent cells – those that can no longer divide to create new cells – removed through the injection of Foxo4-DRI live longer. This compound essentially interferes with the normal process that would tell the cell to stop dividing. These mice are now 30 months old, which is approximately the equivalent of 100 human years, and remain active, proving the effect is not temporary. “If you target so-called bad senescent cells, which are unwanted as they have become old and irreparably damaged, then you can extend and, to a degree, even restore health,” explains Peter de Keizer of the Department of Molecular Genetics at Erasmus University Medical Centre. “By targeting these cells, ageing could not only be delayed, but also, to a degree at least, reversed.”
Meanwhile, Calico, a subdivision of Google’s parent company Alphabet, intends to harness advanced technologies in order to understand the biology that controls lifespan and to use that knowledge to devise interventions that will enable people to lead longer and healthier lives.
So what are the implications if these techniques succeed in radically extending life? One possible issue around people living longer is that it would add to the effects of over-population, an increasing concern in the 21st Century.
In 2015, the number of children born to mothers in England and Wales was, on average, approximately 1.8 children. As society has become more educated and health has improved, the biological imperative for families to have lots of children to compensate for those who did not survive has become redundant. Further, the average age of women giving birth has increased to 30.3 years and there is a growing number of women who have no wish to have children. “Many countries have gone down to, or near to, replacement levels,” observes Sarah Harper, professor of gerontology at the University of Oxford and director of the Royal Institution of Great Britain.
Mice that have had senescent cells removed live longer, healthier lives (Credit: Alamy)
There is also the ethical conundrum that, unless age regression treatment is made available to all, there is a danger of a two-tier society being established, based upon who has access to the treatment. We already live in a world of massive social inequalities. “A child born in the slums of Nairobi has quite different life chances to a child born in Kensington [in London],” says Falkingham.
Should age-extension treatment be equally distributed, then it would also face us with the consequences of a growing elderly population.
The oldest living person ever recorded was Jeanne Calment from France, who lived for 122 years (1875 to 1997). Since health care has continually improved since that time, it is surprising that this record has not yet been surpassed. However, it seems we are genetically predisposed to die once we reach to certain age. “There was a paper that came out in 2016 that argued we might not be able to live longer than 120 years,” says de Keizer.
Much of the current medical research is not about living longer, but rather living healthier for longer, and delaying infirmity
Others think differently. Aubrey De Grey, professor at the SENS Foundation, believes the human lifespan could soon extend dramatically to 1,000. However, as Falkingham observes, “Not very many people agree with him.”
Many elderly people struggle with conditions like cancer, heart disease, dementia and others. Much of the current medical research is not about living longer, but rather living healthier for longer, and delaying infirmity. “It is far better to put all our resources into having everyone have long and healthy life spans,” says Harper.
Rejuvenation treatments may address the physical aspects of ageing, however they do not address the mental and neurological elements, such as Alzheimer’s and dementia. That being said, the number of reported cases of dementia is reducing. “One theory is that just as we keep our bodies active our bodies tend to decline slower, so there is an argument that as we keep our mental activities higher maybe we ward off dementia,” says Harper.
Blood transfusions from young donors can positively affect the health of older patients (Credit: Alamy)
Another aspect to us living longer and healthier lives is that our chronological age becomes increasingly meaningless when defining our lives. There are now 40-year-old women who are giving birth for the first time, as well as other 40-year-old women who are becoming grandmothers. Despite their shared age, their lives have little in common.
In spite of us living longer, our 20s and 30s remain demographically dense, in that we are still having children and starting careers during those decades. “Although we are extending life expectancy, we are not changing our biological time,” says Falkingham. “The period in which women give birth is still in our 20s and 30s.”
Age regression treatments are also expensive. Even if Foxo4-DRI treatment was cleared for use in humans, it costs approximately a few thousand euros for 10mg. And blood transfusions? Well, this supply is very limited. Only 4% of the UK population are blood donors, which is just 1% over what medical and research industries need. Of these 4%, not all will be happy donating blood for age regression.
We would need incredible advances in our understanding of human science to fully prevent human ageing
This scarcity of supply also raises the macabre possibility of a black market where young people are forced or coerced into providing their blood, as well as the dangers of unlicensed dealers selling fake plasma, or that which is unfit for infusion. If this seems overly dramatic, then all we need to consider is how the health industry has become a profitable sector for organised crime. Europol stated, in their recent Serious and Organised Crime Threat Assessment: “The distribution of counterfeit pharmaceutical products online is particularly dangerous.” One recent operation resulted in the seizure of potentially dangerous medicines worth £45m ($58.5m).
Children born in Kenyan slums have a very different life expectancy to those born in the rich cities of the West (Credit: Alamy)
We would need incredible advances in our understanding of human science to fully prevent human ageing, and to even predictably delay it seems a tall order. Further, the ethical, cultural and sociological issues of eradicating ageing would need to be robustly discussed.
“Part of being human is that we have a finite life and that we pace our lives,” concludes Harper. “It is far better to put all our resources into having everyone living long and healthy lifespans, rather than having a few people to live into the far future.”
If you liked this story, sign up for the weekly bbc.com features newsletter, called “If You Only Read 6 Things This Week”. A handpicked selection of stories from BBC Future, Earth, Culture, Capital, and Travel, delivered to your inbox every Friday.