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Human Enhancement

Enhancing Human Lifespan

Bennett Foddy proposes a strategy for extending our youthfulness.

In England during the 1850s one in six people died before their first birthday, mostly from infectious diseases such as cholera, tuberculosis and diphtheria. The average life lasted only forty-two years – but if you made it to fifty you could reasonably expect to live another twenty years. That’s the nature of infectious disease: it singles out the very young and the very old.

It was also in the 1850s that the germ theory of disease began to gain acceptance, leading to the gradual eradication of pathogens from the human environment. Sterilization, sanitation, pasteurization, vaccination, and antibiotics vastly relieved the burden of infectious disease from the industrialized world. By 1983, only about one percent of first-world citizens died before reaching their first birthday, and on average we were living until seventy-five. The elderly, too, were delivered from tuberculosis and diphtheria, freed to be killed by cancer or heart disease instead. Today nearly everyone in the developed world lives long enough to be killed by a heart attack, a stroke, or a tumour of some kind.

The average length of a human life has continued to increase, now up to eighty-one for people born in England. Perhaps more surprisingly, the life expectancy of the very old is rocketing: if you’re eighty, you can expect to make it to eighty-nine. If you make it to ninety you can expect to celebrate your ninety-fifth. What’s going on? The answer, of course, is that we’re getting better at treating cancer and heart disease, the two major remaining medical bogeymen. Nearly 70% of people who are diagnosed with some form of cancer will now live at least another five years – up from just under 50% in 1975.

But there is a price we pay for the ongoing increase in lifespan: we live a higher percentage of our lives in poor health due to old age. Although our medical advances have granted us forty extra years of life, the demographer John Wilmoth estimates that they have given us only ten additional years of vitality. So though we live longer and have more good years, our lives are now worse in terms of the proportion of our years lived in good health, and far, far worse in terms of the amount it costs to keep us going until we die of old age.

DNS syringe

The Waiting Game

To understand why things are turning out this way, one need only look at how we go about keeping the elderly alive. The essence of our universal strategy is simple: we wait. We wait until some age-related ailment brings you to a doctor. Only then, once it’s clear that this ailment is seriously diminishing your health, or even threatening your life, do we spring into action and try to patch you up. If old age brings on cancer, your doctor removes a lump of you and gives you chemotherapy. If it brings on heart disease, you might get a bypass, or a stent, and blood thinners. If you’re diagnosed with osteoporosis, or dementia, or Parkinson’s disease, you get expensive drug-based therapies. But eventually the ailments pile up until you simply cannot be kept alive any longer.

Each of these last-minute life-saving interventions is an expression of what Alan Jonsen calls the rule of rescue. This isn’t a law or an explicit policy, it’s a psychological or philosophical position that undergirds the provision of medicine at every level throughout every country in the developed world. The rule is simple: when someone’s life is identifiably at risk, we try to save it, no matter if they have put it at risk themselves, no matter what their life will be like afterwards, and no matter if they are unable to foot the bill.

Britain’s National Health Service (the NHS) performs some rationing of medical interventions, but the NHS rationing committee (NICE) claims that it only discriminates against the elderly for life-saving technologies that cost more than £1 million. Meanwhile, preventative therapies draw the short straw in public health allocations. The NHS, which is more progressive than most similar health services, spends 2.5% of its yearly budget on statins, a type of drug which can help prevent heart disease in people with high cholesterol. Although it is agreed that this particular program will save money in the long term, statin therapy faces stubborn opposition from politicians and the public, just like every other preventative programme. As a result of this political climate, the NHS spends only 4% of its budget on the prevention of disease.

Last-minute life-saving interventions are guaranteed to extend life without extending youth. If we want to live longer in good health and with the vigour of youth, we need to spend more on the prevention of the ailments that come with age. Sanitation is a preventative medical technology. So is hygiene, and vaccination, and pasteurization. We have conquered infectious disease and doubled the length of our lives mainly through the application of preventative interventions based on then-cutting-edge medical science. But today we spend very little on developing new state-of-the-art preventative medicines, which might give us more youthful years. We have turned our collective eye to life-saving instead of life-lengthening, and that’s why we’re spending more of our lives in decrepitude, and why the medical costs of every developed society are ballooning.

Treating Old Age

Over recent years, the science of the fundamental mechanisms of human ageing and the disorders and diseases caused by it has come a very long way. In the light of groundbreaking experimental results, many theories have been advanced to explain how we age. According to the free radical theory of ageing, for example, all the major processes of ageing are explained by the effects of highly reactive molecules oxidizing our cellular machinery. According to evolutionary theories of ageing, we age because we have evolved genes which change their function over time, becoming gradually more harmful and less helpful as we grow older. What is becoming apparent is that no single theory will explain every aspect of human ageing. Aging is comprised of an enormous list of harmful processes, some of which are built into our DNA and some of which are down to stressors in our environment. Yet at least in theory, each one of these processes could be addressed using medical technology. We are now at a point where we can spend money on the development of medicines which slow or halt the processes of ageing. Yet the rule of rescue guarantees that we will not direct much of our public health or research budgets towards anti-ageing medicine. Any medicine which reversed or halted the ageing process would be worth taking long before age began to threaten our lives – we would want to take it in our thirties, perhaps even earlier. But any medicine we took in our youth would do nothing to rescue any identified endangered individuals from the Grim Reaper. It would be an archetypally preventive medical technology. For this reason, our default approach to healthcare is guaranteed not to provide the kind of lifespan-enhancing medicines that will soon become scientifically possible. As well as this serious practical barrier, anti-ageing medicine is beset by an enormous sense of distrust among philosophers, scientists, politicians and the general public. People see life-extending medicine as a form of excess, perhaps more than any other form of enhancement.

The philosophical arguments against using medicine to cure ageing are rife. Bernard Williams thought life would get too tiresome if we live too long. Carole Haber says anti-ageing medicine would “demean and marginalize the very process of growing old.” (‘Life Extension and History’, Journal of Gerontology, 2004, vol. 59a, No. 6). And Michael Sandel thinks that every human quality, including the ability to grow old and die, is a gift we ought to appreciate with due reverence. There are more reasonable objections, too, many of which were put forward by Mary Midgley in her article in Issue 89 of this magazine. These include the argument that anti-ageing medicine would mean taking more than one’s fair share of the world’s resources, or the argument that these medicines will tend to find their way into the hands of the rich, worsening inequalities that are already pretty bad.

However, for better or worse, I can see at least one way we can dissolve the philosophical arguments against anti-ageing medicine, the public distrust, and the considerable obstacles imposed by the rule of rescue. It involves nothing more than a renaming of certain medical ideas. Instead of seeking funding for the science of ageing and the development of anti-ageing medicine, hopelessly preventative as that is, we could redefine ageing as a set of life-threatening diseases.

Now, several authors have recommended that we consider ageing as a wholeto be a kind of genetic disease, or as a ubiquitous injury we all eventually sustain in a hopelessly dangerous world. But this seems impractical, even if it is philosophically sound. In the first place, age has grown far too familiar for us to ever really see it as a disease. More importantly, if we take ageing as a single disease, it is a disease which sets in far too early and far too gradually to be something we might feel compelled to rescue someone from. We aren’t moved to rescue people from continental drift, or from ice ages caused by the Earth’s orbit, even though these things could bring millions of lives to a premature end.

The alternative is to stop conceiving of ageing as a unitary thing. Rather than talking about ‘age-related processes of cellular damage like oxidation’, we could speak of ‘cellular oxidation disease’. Rather than funding research into apoptosis, the genetically-programmed cell death that occurs en masse in older organs, we could raise the alarm about ‘congenital apoptotic disease’. These ‘age diseases’ do not have a familiar face to make them seem natural, as old age itself does; and they are precisely the kind of thing from which it might seem reasonable to rescue someone – diseases diagnosed late in life which cause harmful and eventually life-threatening symptoms.

What Is A Disease?

This may seem ridiculous on the face of things: how can the processes of ageing be diseases, when they are natural functions of the body, present in every individual?

Of course, the boundary between disease and natural functioning is not so sharp. Consider heart disease, which is a spectrum of congenital and environmental processes that effects nearly everybody in their old age. Consider dementia, which is also officially classified as a disease. These things are also age-related processes that are harmful, but natural, and present in every single human being, so long as the human being lives long enough to see them. And there is the money and the political will for understanding and curing heart disease and dementia.

What is a disease, after all? The philosopher Christopher Boorse from the University of Delaware takes the view that a disease is a loss of function in an organ relative to a statistical norm. On that view, the processes that constitute ageing cannot reasonably be considered diseases so long as they happen at the normal rate and set in at the normal age. But as a consequence, heart disease and dementia cannot be diseases either. In order to call heart disease a disease, we need rather to use a normative concept of disease. For example, we could argue that a disease is any biological state that reduces our overall flourishing or wellbeing. In that sense, the processes of ageing certainly qualify as diseases, as do any normal but harmful human functions.

The reason we prefer to say that dementia and heart disease are diseases, is precisely that it makes it easier to justify spending money on saving people from them. In an emotional and psychological sense, we will save you from a disease, but not from a natural change in the functioning of your body. We could take the same approach with ageing. This would defuse many of the philosophical objections as well. It’s hard to imagine Carole Haber objecting that curing someone’s ‘congenital apoptotic disease’ would devalue the elderly, or Bernard Williams suggesting that life would be insufferably dull if we no longer suffered from ‘oxidation disease’ (or heart disease, or dementia, for that matter). People would support the eradication of these diseases, just as they support the eradication of typhoid, diphtheria, and cholera. And just as in the case of those diseases, the development of cures for these new age-related ailments would lead to another significant upswing in the length of human life.

Perhaps this conceptual strategy would only serve to sweep important ethical and philosophical questions under the rug. Perhaps we should first be asking whether we really want to live a lot longer, or whether we should live a lot longer. Perhaps we shouldn’t call something a disease if it affects everybody equally. These are interesting questions – and perhaps they’re questions we should also ask of those who provide treatments for heart disease and dementia, since those treatments make us live longer too. But whether we answer these questions or not, we have already charted a course. We apply the rule of rescue every day – and the effect is that every year we get a little older, a little more decrepit, and a lot more expensive to keep alive.

Bennett Foddy is Deputy Director and Senior Research Fellow at the Institute for Science & Ethics, University of Oxford.