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| The cost of living |
27-Jul-2005 |
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THE BIG PICTURE by Professor Stephen Leeder
MANY people have made fools of themselves by prophesying that technology would not advance beyond current visible limits, that there would be only a limited worldwide demand for computers, that we would never travel beyond the speed of sound, and that the code of the human genome would forever elude us.
Therefore, it would be dangerous to dismiss new technological interest in prolonging the human life span.
Recently I participated in a public forum in Sydney sponsored by Cosmos, a new magazine that modestly proclaims its interest in “the science of everything”. The forum was entitled ‘A Beginner’s Guide To Immortality’ and was triggered by an article called ‘Living Forever’, by Karen McGhee, in the July issue of Cosmos.
Clinicians offer at present a range of clinical anti-ageing remedies, including hormone (especially growth hormone) replacement. However, the new research focuses on genes. Researchers have identified genes that control the rate at which organisms age. These genes appear to be ancient and are present in the earliest life forms.
A family of genes, the ‘sirtuans’, regulate ageing. Inserting extra copies of these genes cause cells to live longer. Mammals possess seven sirtuan genes. Some molecules have the same effect on life span as increasing the number of sirtuan genes. One of these molecules is resveratrol. In 2003, a Harvard team reported that resveratrol increased the life span of yeast cells by 70%. Last year resveratrol was used to slow ageing in fruit flies and nematodes.
The Japanese city of Okinawa has a population akin to the biblical characters at the time of Methuselah, with the world’s highest proportion of people surviving to 100 years or more — 40 per 100,000 — as well as the world’s longest average life span. Australia, with a population of 20 million, has 2500-3000 centenarians — about one-third of the rate in Okinawa.
“Compared with their Western counterparts,” writes Ms McGhee, “Okinawans suffer considerably lower rates of all age-related diseases: breast, prostate and colon cancers; dementia; hip fractures; heart attacks; and CVD.” Okinawans have a custom of eating until two-thirds full, and indeed, in experimental animals calorie restriction extends life, and may do so via sirtuan genes.
The organisers of the forum did not ask me to participate because of my expertise in the genetic science of life extension. Rather, they invited me to comment on the implications of extending the human life span. What would be our ethical response, as acommunity, to technology that could keep us all healthily alive until 120 years of age?
The life extension achieved through conventional medical technology and improved lifestyle already puts us on notice. The recent report from the Productivity Commission on ageing estimates that the costs of aged care in Australia will increase by about 2.6 times the growth of GDP in the next 40 years. Hospital expenditure remains the largest component of the cost, although its share will fall slightly. Expenditure on pharmaceuticals will see the largest increase. Costs per person in the PBS are strongly age-related — average costs for a male aged 65-74 are more than 18 times those for a male aged 15-24.
The proportion of the oldest old (people aged over 85 years) will increase even more. The share of the oldest old will increase from 1.4% of the population in 2001/02 to 5% by 2044/45, an increase in the number of the oldest old from 277,000 to 1.4 million by 2044/45.
As a share of GDP, the Productivity Commission estimates that costs of care will rise from 0.85% of GDP in 2002/03 to about 2.24% in 2044/45. While these costs are bearable, quadrupling them with life-extension drugs is not, although much would depend upon the quality of the extended life. If 120 became the average life expectancy, then age at retirement would rise to 115!
Interestingly, when members of the forum audience aged 30-35 were asked if they would like to live to an old age, very few said they wanted to live beyond 85.
If technology progresses to enable life extension, the difficult debate that we are having now about how to organise our society to incorporate older people may have been worth it. Maybe we ain’t seen nothin’ yet.
Professor Leeder is director of the Australian Health Policy Institute.
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