the Nuffield foundation, which he published in his book
The first chair for geriatrics in the world was the Cargill Chair at Glasgow University, awarded to Dr Ferguson Anderson in 1965. Alex Comfort, more famous perhaps as a novelist and for writing
In the US the first head of the Unit on Aging within the Division of Chemotherapy at the National Institutes of Health, Nathan Wetherwell Shock, was appointed in 1940. In 1948, the gerontology branch was moved to be under the National Heart Institute. An attempt was made to have an Institute of Ageing established with Heart as a subsidiary, but this failed, as a physician to the Senate stated, ‘We don’t need research on Ageing. All we need to do is go into the library and read what has been published.’ This contrasts with Nathan Wetherwell Shock’s own viewpoint, enunciated just before his death in 1989: ‘I would remind you that we were formed and nurtured in the firm belief that the biological phenomenon we call “ageing” was worthy of scientific pursuit. We have achieved some degree of success. I would caution, however, that our future will be determined only, and only, by the quality of our scientific research on understanding the basic mechanisms of ageing processes.’ In 1974, Congress granted authority to form the National Institute of Aging to provide leadership in ageing research and training.
Research on ageing expanded significantly as it was realised that life expectancy was increasing, and thus the number of elderly. The Gerontological Society of America was founded in 1946 and the field has grown very fast. There are now many scientific journals devoted to the topic, such as
I think doctors struggle with ageing as their training is to diagnose and treat diseases—they want to cure someone. For them ageing is a medical failure. There is a little progress with age-related diseases. It may be possible to cure Alzheimer’s but this is very difficult and prevention is more promising. There has not been enough research on very old people, which is what we are doing in Newcastle. Not a single person in our study over 85 has zero age-related disease, most have four or five.
6. Evolving
‘Getting older is no problem. You just have to live long enough’
Research into the nature of ageing has helped us to understand its mechanisms first in terms of evolution, and then cell behaviour. We are essentially a society of cells and all our functions are determined by the activities of our cells. Evolution plays a key role, since it has selected cells to behave in a way that gives organisms reproductive success—a fundamental feature of Darwinian evolution. Evolution is not interested in health but only in reproductive success. Almost all the features of an organism, including of course humans, have been selected on this basis. The fertilised egg gives rise by division to all the cells that make up our body, as well as those of all other animals. Genes are turned on and off during the development of the embryo and this determines when and where particular proteins are made in cells and so also their behaviour. The details of this process have been selected for during evolution to give rise to adults that will reproduce.
Has ageing also been selected, and is it adaptive in that it helps reproduction? There have been suggestions that ageing was selected in order to reduce the number of adults so they did not compete with each other and so reduce reproduction in the group, but there is evidence to show that this is wrong.
It is essential to distinguish changes with time as an organism develops, and later grows, from the process of ageing. Ageing is not similar to the other biological changes that we go through with time as we develop in the embryo, and then grow older and mature after birth. An embryo gets older from the time it is fertilised, and the most obvious change with age after birth is growth itself, which is part of our genetically controlled developmental programme. We continue to grow for some 16 years. Puberty begins around 11 years and is the period of transition from childhood to adolescence, marked by the development of secondary sexual characteristics, accelerated growth, behavioural changes, and eventual attainment of reproductive capacity. Puberty changes occur as a consequence of the activation of a complex system that leads to an increase in frequency and amplitude of the hormones which stimulate the growth of sexual organs. This system is active in the early infancy periods, but becomes relatively quiescent during childhood, and puberty is marked by its reactivation leading to sexual maturity.
A remarkable case of failure to grow is Brooke Greenberg, a girl from Maryland who at 17 years old remained physically and cognitively similar to a toddler, despite her increasing age. She was about 30 inches tall, weighed about 16 pounds and had an estimated mental age of 9 months to 1 year. Brooke’s doctors termed her condition Syndrome X.
Another major change with age is that each of us will have two successive sets of teeth. The baby teeth begin to erupt at the age of around six months. Usually by 2 years old most of a child’s baby teeth will be in place. Some children get their teeth early, others later. Then typically by the age of 12, all of a child’s baby teeth will have fallen out and been sequentially replaced by a second set of teeth.
All these changes with age are quite different from ageing with its negative effects, and have been selected in evolution as part of our development programme to help with reproduction. So why do we have the negative effects of ageing? Was ageing selected and programmed into our development?
The blame must fall heavily on evolution. To repeat, evolution is only interested in reproduction and not in health once we have reproduced. Ageing, as we shall see, is due to the accumulation of damage in our cells with time. Ageing is not part of our developmental programme and there are no normal genes that promote ageing, though as we shall see there are changes in genes which can cause premature ageing. On the contrary, evolution has sensibly selected cell activities that prevent the damage in cells due to ageing, but which are usually only active until reproduction is greatly reduced. No animals die of old age, but they die because of predators and illnesses, including those which are age-related. The effect of evolution can be seen by comparing two-year-old mice with baby elephants at the same age. The mice are already old. Evolution has selected mechanisms to prevent the elephant ageing before it has offspring, and for some elephants old age is only evident from worn-out tusks. Evolution has generated great diversity in lifespan. For example, rats live for 7 years, and squirrels for 12.
As mentioned earlier, August Weismann, the great German theorist and experimental biologist of the nineteenth century, was one of the first biologists to use evolutionary arguments to explain ageing. His initial idea was that there exists a specific death-mechanism designed by natural selection to eliminate the old, and therefore worn-out, members of a population. The purpose of this programmed death of the old is to clean up the living space and to free up resources for younger generations: ‘… there is no reason to expect life to be prolonged beyond the reproductive period; so the end of this period is usually more or less coincident with death.’ Weismann probably came to this idea while reading the following notes of one of Darwin’s contemporaries and a co-discoverer of natural selection, Alfred Russel Wallace, which he later cited in his essay ‘The Duration of Life’:
…when one or more individuals have provided a sufficient number of successors they themselves, as consumers of nourishment in a constantly increasing degree, are an injury to those successors. Natural selection therefore weeds them out, and in many cases favours such races as die almost immediately after they have left successors.
