Time of Our Lives: The Science of Human Aging available in Hardcover
- Pub. Date:
- Oxford University Press, USA
As recent articles about "the graying of America" suggest, a demographic revolution is well underway. The number of people living into extreme old age is increasing dramatically. By the year 2050 one in five of the world's population, including the developing countries, will be 65 or older, a fact which presages profound medical, biological, philosophical, and political changes in the coming century.
In Time of Our Lives, Tom Kirkwood unfolds some of the deepest mysteries of medical science while demolishing some of the most persistent misconceptions. He overturns the almost universally held belief that aging is either necessary or inevitableit isn'tand debunks the idea that there exists a "death gene" that evolved to inhibit population growth. Instead, Kirkwood shows that we age because our genes, evolving at a time when life was "nasty, brutish, and short," placed little priority on the long-term maintenance of our bodies. With such knowledge, along with new insights from genome research, we can devise ways to target the root causes of aging and of age-related diseases such as Alzheimer's and osteoporosis. Expanding his thesis of the "disposable soma," developed over twenty years of research, Kirkwood makes sense of the evolution of aging, explains how aging occurs, and answers fundamental questions like why women live longer than men. He even considers the possibility that human beings will someday have greatly extended life spans or even be free from senescence altogether.
Beautifully written by one of the world's pioneering researchers into the science of aging, Time of Our Lives is a clear, original and, above all, inspiring investigation of a process all of us experience but few of us understand.
|Publisher:||Oxford University Press, USA|
|Product dimensions:||6.30(w) x 9.10(h) x 1.20(d)|
About the Author
Tom Kirkwood is Professor of Biological Gerontology at the University of Manchester and Director of the Manchester-Newcastle Joint Center on Aging. He is a member of several international editorial boards and scientific committees, an adviser to the World Health Organization, and winner of the Heinz Karger Prize on cellular aging. Mr. Kirkwood lives in Manchester, England.
Read an Excerpt
The funeral season
Light is sweet; at the sight of the sun the eyes are glad. However great the number of years a man may live, let him enjoy them all, and yet remember that dark days will be many.
The journey had been bad enough mile after mile on broken roads through the seating heat and dusty dryness of Africa's Sahel. But the greeting, when the Land Rover finally swung into the driveway of Navrongo hospital, in the Upper East Region of northern Ghana, and came to a halt by a small whitewashed building in the shadow of a giant baobab tree, was very much worse.
'Welcome to Navrongo! The funeral season is just beginning,' said one of the hospital staff with a wide smile as he emerged from the building to greet us.
'Whoops, sorry, wrong place!' I wanted to say and leap back into the Land Rover, racing away to airport, England, and the safe enveloping greyness of a British winter's day. But I didn't, and so began the writing of this book.
A small market town in one of the poorest regions of the world, with no mains electricity, no running water and precious few amenities of any kind, is not the obvious place to write a book about ageing. I should explain that I did not choose Navrongo for this purpose. I was there as an extra, human baggage accompanying an epidemiological investigation of childhood diseases. Perhaps I was also there because Africa was the land of my birth and I have felt its call ever since. The opportunityto spend three months in West Africa had presented itself, and I had eagerly agreed.
No one could deny that Navrongo was an excellent place to study childhood diseases. The local diet was deficient in basic vitamins, the temperature regularly soared above 120 degrees (and that was in the shade), the humidity was barely detectable in the dry season yet was overwhelming in the wet, the water needed to be boiled and filtered before drinking, and parasites of all kinds abounded. Clothes hung out to dry in the open needed pressing carefully with a hot iron to kill the eggs of a parasitic fly which otherwise would hatch into larvae that burrow under your skin. For a child, quite ordinary sicknesses, like diarrhoea and even colds, superimposed on a background of poverty and poor nutrition, easily started a downward spiral that in no time at all could become life threatening. One-quarter of all children born in the region died before they were 5 years old. One might reasonably think that ageing would be far from the minds of the local health authorities, but that would be wrong. It turned out that Navrongo was not such an odd place to think about ageing, as I discovered when I went shopping.
A few miles to the north of Navrongo was the Paga border post, frontier between Ghana and Burkina Faso. This frontier was crossed often, not least because on the northern side soft drinks were cheaper and more regularly available than in Navrongo. On my first journey homewards across the frontier, I found the Ghanaian border post to be staffed by the most courteous immigration officer I have ever had the pleasure to meet.
'Thank you,' I said, as he stamped my passport after careful scrutiny of my visa.
'Thank you for thanking me,' he said in reply.
I was pondering this curious reply, wondering whether to escalate the thanks and risk staying all day, when my eye was caught by a printed poster on the wall.
'Young Today Old Tomorrow. Take Care of the Elderly,' it proclaimed.
Now this really surprised me. Not only was this particular poster side by side with another one showing how to make oral rehydration solution to prevent death from fluid loss in babies and young children with diarrhoea surely a pressing concern in these parts but here we were in a region of the world where the very fabric of society is woven with the weft of respect for the elderly. There are many tribes in this part of West Africa and their linguistic and cultural roots are extremely diverse, but one thing they all have in common is that the older you get, the higher up the social ladder you climb.
I had had first-hand experience of this just a few days earlier. Driving past a small village I stopped to take a closer look at a mudwailed household compound that was painted in a particularly striking pattern of black and white stripes. As I climbed out of the Land Rover, a small crowd quickly gathered and I asked if I might take a photograph of the building that had caught my interest.
'You must ask the Old Man,' said a lanky youth Whose tattered T-shirt improbably displayed the logo of the Hard Rock Café.
Looking about the crowd, I spied the oldest-looking man, who to my eye qualified as seriously venerable, and advanced to ask his permission.
'Oh no,' he said, clearly embarrassed by my gaffe. 'The Old Man is over there by that tree. Come with me.'
We walked to the shade of a gnarled thorn tree where half-sitting, half-lying was a man who seemed as old as the hills. In all likelihood he was aged no more than 80, but the climate of the Sahel is not kind to the eyes and skin, and dentists are as scarce as snowmen. Permission was asked, a small gift of money offered and graciously accepted, and I was free to look around.
You will understand, then, that I was puzzled by the poster. Back home in England, as in much of the developed world, the elderly get short shrift from the young. 'Buzz off, you old git!' is the sort of cheery greeting an old-age pensioner might expect if he remonstrates with the youth who has just kicked a football in his direction. I could see the point of a poster in my home town exhorting the youth of today to remember that they will be the senior citizens of tomorrow. But in Ghana?
The truth is, of course, that the world is changing, and changing fast. A demographic revolution is happening, the like of which has never been seen before. Nowhere is immune to it, and in some ways it is the traditional gerontocracies, like the West African tribal structures, that face the greatest strains.
The trouble is that a system that puts status and power in the hands of the old, just because they are old, works fine when getting to be really old is a rare occurrence. Not only are the numbers of very old people small enough to make the system workable, but there is a sound logic in trusting to the authority of someone who has been canny and robust enough to outlive his or her peers. (Although West African gerontocracies are generally male-dominated, old women also enjoy enhanced social status.) The longlived are custodians of the tribal wisdom. For instance, they remember the terrible famine of 50 years ago and how it was survived. I am indebted to a distinguished French anthropologist with whom I once shared a somewhat boozy flight for a repellent story, but one sworn to be true, of how a village in Cameroon was saved by an old woman's memories of the way that human faeces were picked over for grains that had been only partly digested and could be washed, cooked and chewed once again for meagre but invaluable sustenance. But the system cannot work as well, if it can work at all, when the old cease to be an élite.
Over the last hundred years a revolution of unprecedented scale has been taking place in the balance of generations. The revolution began in the developed countries that were first to experience industrialisation, economic development and the health-preserving benefits of sanitation and clean drinking water. It has gained pace and is spreading fast.
In nineteenth-century England, survival to old age was a luxury that relatively few could anticipate. The following article from an English newspaper of 14 January 1885 describes the situation:
The Registrar-General has recently published the march of a generation through life in England. He says that of a million persons born alive, the number at the end of five years will be 736,818. At the end of 25 years there will be 684,054 of the million left. At the end of 35 years there will be 568,993. When 45 years have passed, 502,915 will remain. At 65, 309,020 will still be alive. When 75 years have roiled by, 161,164 (or nearly one out of six} will still remain. At 85, only 38,575 will survive. At 95, the million will be reduced to 2,153. The number who cross the line of the century will be 223, and at 108 years from the starting point the last one will be in his grave.
Of course, the last one in his grave was probably a woman, since women generally live longer than men, but, as we shall see in later chapters, that is another story.
We are separated by just four generations from the date of this article, but how the picture has changed. Let us compare the figures from the 1880s with those for the 1990s. We will use the numbers for both sexes combined and assume that the figures in the newspaper article followed usual practice and lumped England and Wales together. In each case, we will track the number of survivors from a million newborn (see Table 1.1).
The change in survival patterns is astonishing. It is worth looking closely at what these figures tell us. First of all, it is clear that England and Wales have got a good deal greyer. Out of a million people born today, five out of every six of them will still be alive at age 65. At current birth rates, by early in the twenty-first century one in five of the population will be aged 65 or older.
The second dramatic alteration is that life expectancy at birth in England and Wales has nearly doubled from some 46 years in the 1880s to around 76 years in the 1990s. Herein lies a potential source of confusion. It is not the case that each person in England and Wales is now living twice as long as his or her Victorian forebears. Life expectancy has doubled because many fewer people are dying young.
Survival in England and Wales in the 1880s and 1990s
|Alive at 5 years||736,818||991,350|
|Alive at 25 years||684,054||984,230|
|Alive at 35 years||568,993||977,500|
|Alive at 45 years||502,915||963,960|
|Alive at 65 years||309,020||830,990|
|Alive at 75 years||161,164||612,740|
|Alive at 85 years||38,575||286,950|
|Alive at 95 years||2,153||45,450|
|Alive at 100 years||223||8,710|
SOURCE: Figures for the 1880s are from the 1885 newspaper account of the Registrar-General's report. Figures for the 1990s were kindly provided by A.R. Thatcher, former Registrar-General of England and Wales.
The bottom half of our table reveals what has happened to the survival rates of the older age groups, which show a significant but more modest improvement. We can calculate the survival rates at these older ages by doing a little arithmetic. For a present-day inhabitant of England and Wales, the chance of surviving to age 75, given that you have already made it to 65, is 612,740 divided by 830,990, or 73 per cent. For a Victorian, the same chance was 161,164 divided by 309,020, which was, even then, a respectable 52 per cent. Indeed, if we measure the further life expectancy of 65-year-olds, we find only a modest increase from around 11 years in the 1880s to around 16 years in the 1990s. The ageing process now is not so very different from what it was then. Even in Victorian times there were those who lived to be a hundred.
The biggest change since the late nineteenth century is revealed in the common causes of death. The most frequent killer in the developed world today is cardiovascular disease disease of the blood circulatory system which accounts for 40-50 per cent of deaths in many first-world countries. Most cardiovascular disease is heart disease leading to heart attacks, although circulatory disease of the brain causing stroke or vascular dementia is also of major importance. Next on the list comes cancer, which in its variety of forms accounts for another 30-40 per cent of deaths. After cardiovascular disease and cancer come accidents, of which car accidents account for about half. Accidents make up around 4 per cent of the total. Chest diseases like emphysema and pneumonia then head a cast of more minor but still important players, including diabetes, liver disease and suicide. Some of the major afflictions of old age, like Alzheimer's disease, do not feature on the list in their own right because they rarely cause death directly; they lurk behind the other killers as contributing factors.
Turn back the clock 100 years, take away our antibiotics and vaccines, and the cast of killers was a very different affair. Top was respiratory disease, not including tuberculosis and influenza. Next were the so-called digestive diseases scourges like typhoid, cholera, dysentery and a host of other ailments. Tuberculosis was a major cause of death in its own right, as was influenza. Diphtheria, croup, measles, whooping cough and scarlet fever were all diseases to be feared, causing many deaths in childhood. And accidents, in the absence of the modern emergency room and with much greater risk of sepsis, were twice the cause of death they now are, even though our love affair with the motor car was then just a twinkle in an occasional eye.
In one sense, travelling to Navrongo was like travelling backwards in time. Mortality rates in the region around modern-day Navrongo are not so very different from those in Victorian England and Wales. A quarter of children die in the first 5 years of life; infectious diseases are still a major cause of death; and accidents, childbirth and malnutrition continue to exact a heavy toll. But in another sense, Navrongo is very different from the England and Wales of the 1880s. The technologies of modern medicine, agriculture, industry and water purification are not waiting to be discovered at some uncertain date in the future. They are with us now and the obstacles to their wider application are economic, social and political.
Demographic change is coming to the third world even faster than it has come to the first. It is coming partly because public health is improving, even in underdeveloped countries, except where progress is undermined by the scourge of AIDS, but also because birth rates are declining. With fewer children being born, and the rest getting older all the time, the average age of the population is going up and up. By the year 2020 just a generation away more than a billion people in the world will be 60 or older, and more than two-thirds of them will be living in developing countries. The whole globe is getting greyer.
There is an unfortunate tendency to see the greying of the world's population as a disaster in the making instead of the twofold triumph that it really is. Firstly, we have managed not a moment too soon to begin to bring soaring population growth under control. Secondly, we have succeeded through vaccination, antibiotics, sanitation, nutrition, education and so on in bringing death rates down. If it turns out now that we lack the will and strategies to accommodate the elderly people that result from these successes, and to realise their potential as a benefit not a burden, then perhaps we should seriously question whether as a species we can justly continue to conduct our affairs under the grandiose title of Homo sapiens.
Coded in the statistics of life and death of the 1880s and 1990s is a message that hints at a profound shift in the psyche of most of the better-off nations of the world: we have lost our intimate familiarity with death.
In the England and Wales of Queen Victoria's day, one in four children died before its fifth birthday. One in fourteen youngsters died between 5 and 25. One in six young adults died between 25 and 35, accidents, infections and childbirth being the major killers. One in nine died between 35 and 45. And one in three died in middle age between 45 and 65. I came to appreciate the enormity of this change during my time in Navrongo.
The funeral season, it turned out, was not the dread prospect it seemed at first. Funerals in Navrongo are not the same as burials, which are simple interments and happen quickly after a person dies. Funerals are ceremonial rites of passage, held months or even years after death. They are organised at great expense to show respect to the spirit of the dead person and to facilitate his or her advancement in the spirit world, in the hope that this will also secure the ancestral spirit's protection and beneficence towards its surviving kin. Funerals are great parties with much eating and drinking that last several days and that draw family and friends from far and wide. There are even special funeral pots of baked clay on sale in the markets, just to hold all the extra food and millet beer. Because funerals are such big affairs, the funeral season happens when agriculture is at a low ebb in the drought months from January to March. Deaths happen all the time.
And death did happen all the time in Navrongo, mostly simple, preventable deaths in childbirth or from malaria that struck down people of any age. Sadly, this included several people within our circle of acquaintance, including a colleague and good friend who returned home to London in apparent health, only to collapse and suffer brain death from an attack of cerebral malaria. This within a small community in a few short months.
This brings me to the sombre side of this opening chapter. A book about ageing is a book that must confront death. Confronting death is something for which, in our privileged world, we are increasingly unprepared psychologically. Death strikes rarely enough that we can deny it to an extent that would seem strange in Navrongo. In the developed world, the physical aspects of dying are increasingly unfamiliar. Deaths mostly happen in hospitals, often with no close kin at the bedside. The time-honoured practice of paying last respects to the corpse has been abandoned in many sections of society. It is small wonder that we have become less comfortable with the whole idea of dying and that talking about it openly has become a hard thing to do. People who have to confront death directly for example, those with terminal illness or the very old do so with the added burden of so much denial around them.
The things we hide by denial in our minds have a habit of springing out and ambushing us when we least expect them. When Diana, Princess of Wales, died in a car accident in Paris in the small hours of 31 August 1997, the traditionally reserved British public surprised themselves by the strength of their emotional reaction. Of course Diana was popular, and of course her death was a tragic loss, but it was not just grief that struck so hard. Shock and disbelief were quite as evident as grief shock at the death of one so full of life, so young. Diana's death was a reminder to us all of what we would much rather forget: our own mortality. Yet by Diana's age a century ago, nearly half of those born in the same year as her would have been dead already.
For most of us today, mortality and ageing are closely intertwined. We don't relish an early death, but we hate the thought of growing old. When we open our minds to the reality of ageing we feel anguish. No one who is in good health, of sound mind, and capable of giving and receiving love, including the proper love of oneself, could feel anything less at the realisation that ageing will rob one's loved ones and oneself of vitality and life. But anguish, like joy, is too strong an emotion to be sustained for long. There is good news on the horizon and a challenge to be met.
The good news is that old people are living longer, healthier lives, and that the remarkable improvements in survival are continuing. The 85+ age group is currently the fastest-growing sector of the population in most of the developed countries. There are many who fear that longer lives will mean more ill health and disability, yet there is encouraging evidence that in the United States the period of sickness and disability is actually getting shorter, not longer, as life span increases.
The challenge is to age as successfully as we can. For society, the challenge of successful ageing is a paramount issue touching on all aspects of life social, economic, medical and spiritual. For the individual, the challenge is to reach old age in optimum health and to develop the resources and attitudes to preserve independence and quality of life for as long as possible. To meet these challenges, we need to find out as much as we can about the ageing process. The following chapters will reveal what scientists already understand about why ageing happens and what causes it.
Table of Contents
The Funeral Season
Attitudes to aging
What's in a name?
The unnecessary nature of aging
Why aging occurs
Cells in crisis
Molecules and mistakes
Organs and orchestras
The cancer connection
Menopause and the big bang
Eat less, live longer
Why do women live longer than men?
The Genie of the Genome
In search of Wonka-Vite
Making more time