The relationship between ageing
and disease
3.55. A question of immense significance is the
distinction between the natural ageing processes, and those diseases
which are particularly prevalent in old age. The Medical Research
Council (MRC), the Department of Health (DoH) and the Wellcome
Trust all told us that they directed most of their attention within
the field towards diseases and disabilities, with relatively little
focus on the ageing process itself. In contrast, the Biotechnology
and Biological Sciences Research Council (BBSRC) focused on underpinning
mechanisms of ageing and not directly on diseases.
3.56. Within the United States, we heard from
the National Institute on Aging that they drew a distinction between
the two areas, but found funding research into specific diseases
much easier; much of their research was therefore disease-related.
On the other hand the Ellison Medical Foundation, a private foundation
investing $20 million annually on ageing, concentrated more on
basic research. Dr Richard Sprott, the Executive Director of the
Foundation, told us he felt that the funding of research was too
much orientated towards research into diseases, to the exclusion
of the basic underlying science.
3.57. Although we could understand the reasons
why different organisations should focus more on ageing or on
disease, we quickly discovered that the distinction is not always
a clear one. Professor Cyrus Cooper, who gave evidence to us on
behalf of the National Osteoporosis Society and the Arthritis
Research Campaign, explained that this was particularly true in
the rheumatological arena. Bone mineral density and the thickness
of the cartilage of the joint changed with age, leading to an
increasing risk of the likelihood of the adverse health event:
fractures and osteoporosis, joint pain, disability and osteoarthritis.
The original approaches to definition simply picked the threshold
at which it was felt that the risk of disease became unacceptably
high, and set the definition at that point. Definitions were now
more sophisticated, but there was still no very clear distinction
between gradual deterioration with age, and the stage at which
it was appropriate to say that a person was suffering from a disease
(Q 47).
3.58. Furthermore, it may sometimes be difficult
and unhelpful to distinguish between age-related diseases and
the deterioration which results from them. It seems to us that
whilst specific diseases and disabilities are the manifestations
of growing older, there are underlying basic processes that inevitably
age us which are to be found in the mechanisms contributing to
the accumulation of molecular and cellular damage. In the words
of Professor Linda Partridge, Weldon Professor of Biometry, University
College London, "what we are looking at is an underlying
process of progressive loss of function that leads to increasing
vulnerability to various diseases
there is an underlying
ageing process that can affect all these diseases simultaneously"
(Q 387).
3.59. However in the majority of fields, witnesses
thought that a helpful distinction could be drawn. The Royal College
of Physicians of Edinburgh agreed that "the crucial distinction
between the effects of age alone and the effects of disease require[s]
to be reinforced in the minds of both the lay public and health
professionals".[63]
3.60. Professor Clive Ballard, Director of Research
at the Alzheimer's Society, supported this view:
"It is not ageing itself that causes the
problems but the diseases that become more common with ageing.
If you look at the age of a particular population then the risk
of particular conditions will be higher, but that is because the
underlying factors that contribute to these conditions become
higher rather than that age itself causes problems per se."
(Q 308)
3.61. Dr van der Ouderaa said: "I think
it is helpful to discriminate between age related diseases and
ageing as separate processes from a communication point of view."
However, he qualified this by going on to say: "I think a
lot of the etiological factors are actually quite similar"(Q 123).
Professor Mathers agreed and added: "I tend to think of the
ageing process as a process in which our ability to cope with
perturbations of the norm become more and more difficult. The
ability to maintain homeostasis, if you like, becomes more difficult
so we need to be able to defend that state, and ageing is a way
in which we begin to lose that ability." (Q 124)
3.62. There does seem to be a widely held perception
of such a distinction, which has implications both for finding
the path to scientific understanding and for attitudes. For example,
in the case of cardiovascular disease, if it proves possible to
prevent atherosclerosis (hardening of the arteries) from occurring,
the age-related increase in heart disease and stroke will be greatly
reduced. Whether this will entirely eliminate circulatory problems
that develop with age is less certain, however, and it may be
that in order to prevent atherosclerosis we will need to understand
why older arteries are intrinsically more vulnerable to atherosclerosis
that young ones.
3.63. In terms of attitude, diseases are regarded
as being susceptible of a cure, and deserving of sympathy. Ageing
is thought of as the general lot of mankind, and as something
which must be endured. This affects public attitudesit
is much easier to raise funds for research on specific diseasesand
it also affects the attitudes of professionals. For many doctors,
whose motivation is to cure disease, we suspect that ageing too
often has undertones of failure.
3.64. We believe that there are three reasons
to be cautious about accepting too readily a distinction between
ageing and disease. First, for most age-related diseases, age
itself is the single largest risk factor, so to try to research
the disease without also addressing the underlying process of
ageing seems ill-advised. It may simply be impossible to combat
the one without the other.
3.65. The view that ageing is driven by an accumulation
of cellular and molecular damage is not very different from the
view of the mechanisms responsible for most if not all age-related
diseases, so there is great potential for specific age-related
diseases to share common causative mechanisms not only with ageing
itself but also with other age-related diseases.
3.66. Finally, attempts to maintain a distinction
between ageing and disease are likely to work to the disadvantage
of those who are not "fortunate" enough to have a clearly
recognised disease and who "merely" suffer from the
multiple conditions that tend to afflict older people.
3.67. Most of the research on ageing and health
within the UK is focused on specific diseases and medical conditions
for which age is the single largest risk factor. However, there
is little research on underpinning mechanisms of such diseases
which may be linked to basic processes of ageing. The Department
of Health and other medical research funders, including the major
charities, should develop and implement strategies to address
links between ageing and disease.
3.68. In this chapter, we have considered the
intrinsic processes of ageing. In the following chapter we explore
more closely age-related diseases and disorders.
28