Long life's journey into death

十二月 7, 2007

Human lifespan doubled in the 20th century, but we have largely traded our forebears' short, sharp ends for the exotic diseases of old age and a lingering, painful demise, writes Guy Brown. Once upon a time, Death was young and virile, remorselessly scything through humanity, pervasive, undeniable and unstoppable. Now Death has grown old and is slowly falling apart - a suppressed terror consigned to some attic of our memory. Will Death itself finally expire in the 21st century, holding out the prospect of our immortality? Or will it have the last laugh instead?

Death, as I demonstrate in my book The Living End , is certainly not what it was. Life in a state of nature was once described as "nasty, brutish and short", but this would be a better description of death throughout most of human history. The very shortness of life tended to mean that death, too, was short. People died either as children or in their prime, so ageing and the aged were rare. The most common forms of death were by infections, violence, accident or in childbirth. On the whole, death was rapid: people were fully alive one day and fully dead the next. There was relatively little grey area in between.

During the 20th century the average lifespan in the world doubled, and people in developed countries now tended to die old and slowly from degenerative diseases brought on by ageing. Until recently it was thought that humans had a maximum lifespan that we would hit at some point as death from disease was eliminated. Many limits have been suggested, but each has been shattered by experience. Average lifespan has been increasing at the staggering rate of 2.2 years per decade (or almost five hours per day) for the past 100 years, and there is no sign of this slowing down, even in the countries of highest life expectancy.

Unfortunately, this increase in lifespan has not been matched by an extension of healthy life: the additional years we gain are spent mostly with disability, disease and dementia. Between 1991 and 2001, life expectancy in the UK increased by 2.2 years, according to the Office of National Statistics, but healthy life expectancy increased by only 0.6 years - with the other 1.6 years dogged by ill-health. A linear increase in lifespan is colliding with a roughly exponential increase in age- related degenerative diseases. The result, according to research by Carol Brayne and colleagues at the Institute of Public Health in Cambridge, is that 30 per cent of people dying in the UK today have dementia and 45 per cent have a moderate to severe cognitive deficit. That is scary enough, but worse is to come: of those currently dying at 95 years or older, 58 per cent have dementia, and 80 per cent have moderate to severe cognitive deficit. And this is where we are all headed, unless we take drastic action now.

The vast majority of people in the developed world (and increasingly in the developing world) die from degenerative diseases such as cancer and heart disease. These diseases are caused by age; dying from them is slow and becoming slower, so the processes of death and ageing are merging into one. Death is currently preceded by an average of ten years of chronic ill-health in the UK, and this figure is rising. Few people survive until death without significant physical and/or mental disabilities, sometimes extending over decades. Death has become a long, drawn-out process.

We as a global society have been remarkably successful at taming acute forms of death. Until as recently as 100 years ago, acute death was the norm - now it seems like an outrage. Yet many acute forms of death have been converted to chronic death or disability. Heart attacks have become heart failure; stroke has become vascular dementia; diabetes, Aids, even some cancers have been converted from acute causes of death to chronic disabilities. All these are great medical advances, but they also have a major downside: the conversion of acute into chronic death. This is good news only for the pharmaceutical companies that now dominate medical research. Curing diseases does not pay (you lose your patient), whereas converting an acute disease into a chronic disease pays very handsomely indeed because you turn a short-term patient into a long-term consumer of your drugs.

Patients, medics and funding agencies have, perhaps understandably, been more concerned to prevent death than to prevent disease. Sudden death is generally more "sexy" than chronic death. Just compare the column inches devoted to the acute deaths of young people (for instance, Princess Diana's car crash) and the chronic deaths of old people. Yet the latter is much harder for the individual concerned. We may think that chronic death from old age is "natural", while acute death of the young is somehow unnatural. In reality, of course, the exact opposite is the case.

Death from old age is extremely rare in wild animals and was rare in humans until 100 years ago. Only in the unnatural conditions of modern society and medicine can the exotic diseases and deaths of old age bloom. Many of these diseases and causes of death have been recognised only in the past few decades, and many more undoubtedly lie undiscovered ahead.

How did we get into this iniquitous situation where the end of life is becoming a long drawn-out nightmare? The suppressed dread of death has allowed our society to sleepwalk into a situation where people face real horrors at the end of life, simply because we cannot face dealing with the issue of how people should exit life. Death has been banished to hospitals, the worst possible place to end one's life. Medicine is committed to keeping people alive at any cost, not helping people die. Huge resources are devoted to preventing infectious diseases, stroke and heart attacks - possibly the ideal ways to die - though this inevitably condemns people to die by more protracted means. By attacking death at the end of life we have allowed death-within-life to grow, so that the end of life is often no longer worth living.

As academics we need to ask how far our research is contributing to this mess. According to the 2003 World Health Organisation report The Global Burden of Disease , the relative contributions of different diseases to disability in the aged were: dementia (11 per cent), stroke (9 per cent), musculoskeletal disorders (9 per cent), cardiovascular disease (5 per cent) and all the different forms of cancer (2 per cent). The proportion of research papers (since 2002) devoted to these chronic diseases reveals a starkly different ordering of priorities: cancer 23 per cent, cardiovascular disease 18 per cent, musculoskeletal disorders 7 per cent, stroke 3 per cent and dementia 1 per cent. Research and research funding needs to be redirected at ageing and quality of life, rather than simply at preventing death. We have to develop alternative routes to drug development for therapies that the pharmaceutical and biotech industries do not pursue for economic reasons. Hospices ought to be as ubiquitous and well-funded as maternity hospitals.

Is there any feasible way to escape this mortal fate and claim immortality? Recently, several new "immortalist" movements have sprung up to devise and champion new - scientific or semi-scientific - routes to immortality. Throughout history, people have sought to escape death and claim immortality in three different ways: spiritual, genetic and cultural. We may survive as spirits in some afterlife. We may survive through genes passed on to our children and children's children. Or we may survive though our works, deeds and memories - "memes" - left to our family, friends and society in general. Possible new ways to engineer the survival of the spirit include neuronal-electronic interfaces, whereby consciousness might gradually migrate on to a silicon format or out to the internet. An updated version of genetic survival is cloning. Memetic or cultural survival can be promoted by digital and video archives of people's thoughts, works and deeds.

Optimism about life and death are essential to the individual but can be dangerous for society. Death and ageing will be defining problems of the 21st century. Only by recognising that death is part of life, and that many people experience a living death at the end of theirs, can we make sensible decisions about the future direction of research. If society really cared about the last ten years of life to the same degree as the first ten, we would have a real chance of preventing much of the terrible suffering caused by ageing and dementia before it is too late.

Guy Brown heads a research group on cell death at Cambridge University. The Living End: The Future of Death, Aging and Immortality is published by Palgrave Macmillan, £14.99.



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