Select Committee on Science and Technology Written Evidence

Memorandum by Professor Sir John Grimley Evans

  The idea that some index of functional quality of life should be used to supplement mere longevity as an indicator of the success of health and social influences on ageing was first set out systematically in a WHO publication of 19841. That report summarised a population-based perspective on later-life trajectories characterised by transitions from health active life into morbidity (ill health) on through disability to death. Most geratologists have since focused on disability rather than morbidity as the crucial transition, because it is disability and its associated loss of autonomy that older people fear, and which in turn leads to dependency with its cost implications for the health and social services. Moreover, much of modern medicine as applied to older people does not "cure" disease but relieves its symptoms and other effects and, in the best case, prolongs survival. People may still have the "disease" in a medical sense but it does not affect their quality of life. Such effects ought surely to register as success in prolonging disability-free life expectancy, rather than as failure in extending the duration of (irrelevant) "disease".

  Health, especially self-rated health, is a slippery entity dependent on concepts and definitions of disease, exposure to medical diagnosis and therapy, and the various social factors that set the relative benefits and costs of declaring oneself as "unhealthy". There is also no necessary or direct link between states of health and functional capability or sense of autonomy. Disability, however, can be defined and assessed for research purposes. Admittedly, there have been some different approaches to the concept in the literature, and the WHO confused the issue some years ago with a somewhat idiosyncratic use of the term. None the less, the notion of disability defined by inability to perform some desired activity that it is reasonable and socially appropriate to want to do is a generally accepted tradition with a long history2. In essence, disability arises when there is an "ecological gap" between what a person can do and what his or her environment demands. There are disabling environments as well as disabled people.

  I would urge the Committee to focus on disability-free life expectancy rather than healthy life expectancy as a measure of the well-being of an ageing population.

  Although there is still debate over the details of the time trajectory it is now generally accepted that the prevalence of disability in later life has fallen in the United States since the 1980s3. As far as the UK is concerned, the informed view is that we simply do not know what is happening, but there is certainly no evidence that disability levels in later life are falling as in the USA. Researchers have done their best with the data from the General Household Survey but the Survey was not designed for the purpose and the self-reported data are subject to various forms of bias and distortion that can affect the evaluation of time trends. Self-reported data from questionnaires are not optimal for measuring the prevalence of disability in the population, and supplementary information from objective measures of functional abilities is required. There is extensive experience in the USA in the assessment of disability in the community that could be drawn on.

  There can be no doubt that what has happened in the USA could be made to happen here through appropriate and co-ordinated health, social, and educational policy (see Table). It is therefore highly desirable that disability-free life expectancy in the general population should be monitored. The data could be used to assess the effectiveness of relevant government policies and provide a more secure basis for identifying current shortfalls and predicting future needs for health and social services.

  There could be a perceived conflict of interest if the Department of Health, responsible for aspects of relevant policy, were to be charged also with the collection of data to be used for assessing the effectiveness of policy. While experienced researchers would need to be involved, the Office for National Statistics would be the most appropriate body to oversee the necessary repeated standardised surveys.



Postponement as prevention* Lifestyle
Knowledge, opportunities, incentives
Public health and medical care
Disability-reducing interventionsSurgical
Less disabling environmentsWealth distribution
Architecture and planning
*Because of age-associated loss of adaptability the older we are when struck by a potentially disabling disease, such as stroke or coronary disease, the more likely we are to die rapidly rather than linger in a disabled state.


1  World Health Organisation Scientific Group on the Epidemiology of Ageing (1984). The uses of epidemiology in the study of the elderly. Technical Report Series No 706. Geneva: World Health Organisation.

2  Verbrugge LM, Jette AM. The disablement process. Soc Sci Med 1994; 38: 1-14.

3  Manton KG, Gu X (2001). Changes in the prevalence of chronic disability in the United States black and nonblack population above age 65 from 1982 to 1999. Proc Natl Acad Sci USA; 98: 6354-6359.

4  Grimley Evans J (2003) Live longer, die faster: an attainable aim.!gid2=2370

March 2005

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