ANNUAL SYMPOSIUM

Australia's science future 3-4 May 2000
Full listing of papers

Dr Julie Byles is Senior Lecturer in Clinical Epidemiology at the University of Newcastle and Director of the Hunter Institute for Ageing Research. Her research interests in ageing include determining physical, psychological and social factors associated with 'positive ageing', and the role of health services in maintaining quality of life for older people. Dr Byles is an investigator on the Australian Longitudinal Study on Women's Health; she is responsible for the oldest cohort, which involves over 10,000 women currently aged 75 to 78 years. She is also the lead investigator on the Department of Veterans’ Affairs' Preventive Care Trial – a ten-centre randomised controlled trial of the effectiveness of health assessments for older Australian veterans and war widows.

Research for an older, healthier Australia
by Julie Byles
jbyles@cceb.newcastle.edu.au

Abstract
Is it a triumph that more people are living longer or a tribulation for a society that will have to provide for them? The answer depends on how well we plan for, resource and implement health care and services for this growing population, and on how much we can anticipate and prevent morbidity in older age. Until recently, advances in public health have focused on preventing diseases with a high mortality (eg, cancer, cardiovascular disease). The new challenge is to prevent those conditions that cause the greatest disability, dependency and loss of quality of life, and to promote those behaviours and situations that contribute to 'healthy ageing'. Dr Byles will present evidence for healthy ageing and give an overview of new directions in public health research to advance this state.

Ageing occurs in a social context. This can have a great impact on the experience of ageing.

The age structure of the population is changing, with more people reaching greater ages. At the same time the birth rate is decreasing, infants are surviving into adulthood and there has been a decline in heart disease, stroke and cancer, largely due to the reduction in smoking.

Does living longer mean being sicker longer? We want people who are old and healthy. At the end of life there is often a period of misery and ill health. Compression of this period may not occur as a natural product of living longer. US studies show that people in higher socioeconomic levels with healthy lifestyles have less ill health in old age.

The role of health promotion needs to change. Rather than trying to add years to life, it should be trying to add life to years. The old priorities were the causes of death. The new priorities are the problems that cause a loss of healthy life. At the top of this list is depression, with arthritis and sleep difficulties also common.

If we concentrate on heart disease we will extend the misery period. If we can prevent arthritis, we will compress the misery.

New actions should be:

• to identify needs;
• to treat, with rational use of appropriate medicines (the use of inappropriate medicines is a major cause of admission to nursing homes);
• to vaccinate, which is little promoted for older people;
• to encourage good nutrition, which can be compromised for social or physical reasons;
• to prevent accidents and injuries;
• to encourage physical, social and productive activity.

An Australian study of women’s health in 1996 and 1999 showed that the factors that improve the health of 70 to 75-year-olds are physical, social and productive activities. People who take more exercise have fewer symptoms.

We need to redefine health; it is not just the absence of disease and infirmity. Then we can have a positive view of ageing as a time which offers time, freedom, wisdom and calm, with benefits to the community through the activities of older people in caring for others.

Session discussion

Productive activity increases vitality. Does depression lead to less productive feelings and suicide?

Julie Byles. Reactive depression is more common among older people. We are still coming to grips with the impact of war-related events on late-life depression.

Rob Helme. Pain and depression particularly affect older age groups.

Stroke is one of the most common causes of disability and yet doctors don’t treat hypertension in older people. That is extremely undesirable.

Julie Byles. One of the problems in treating hypertension in older people is the lag between research results and changes in the prescribing behaviour of doctors. We need a change of view.

Mice with their telomerase template knocked out still aged normally. How do you explain this?

Roger Reddel. They aged normally until the telomeres became short. After six generations the telomeres had become very short, the males were sterile, and there were some signs of premature ageing. However, the role of telomere shortening in the ageing of normal animals needs a lot more study.

How long are the telomeres in cancers?

Roger Reddel. The telomeres of cancer cells can be long or short. But the important point is that the cancer cells are able to keep their telomeres at a fairly constant length. In other words, they avoid the inexorable telomere shortening that occurs during the proliferation of normal cells. In most cases, cancer cells use telomerase to maintain their telomeres, but there is also another process that they can use. So one of the concerns about switching on telomerase in normal cells would be that it increases the risk that they will later become cancer cells. But we could switch on telomerase in normal cells, use them to reconstruct an organ, and then get rid of the telomerase gene. We already have ways to do this.

Burnet started eating zinc sulphate in his seventies. Is it prophylactic for ageing?

Zeinab Khalil. I am not aware of any studies. There is a link between zinc and Alzheimer’s disease.

There has been a study of ageing in women. Is there a study of men’s health in Australia?

Julie Byles. The study was a result of the women’s health movement. A men’s study would require a political decision, with government funding. Men may be quite different, for example, in their need for social interactions.

Rob Helme. Other studies have small numbers and variable outcomes. We need to do some genetic epidemiology in this country.

 

Studies at the Australian National University have been testing people at intervals of four and five years.

How long do you delay using antioxidants after injury?

Zeinab Khalil. One week.

Does a decrease in calorie intake slow ageing?

Zeinab Khalil. A decrease in calorie intake increases lifespan and decreases oxygen free radicals. It is one anti-ageing strategy. But how many of us could cope with it? Hungry rats lived four years instead of the normal two years.

What happens if you transplant organs from a short-lived species to a longer-lived species?

Roger Reddel. It is hard to predict. The tissue’s proliferative capacity may not be the limiting factor. Immunity may be more important.

Social contact appears to improve old people’s lives. Is there a difference between contacts with young or with old?

Julie Byles. The survey did not show the age of contact. But it is an important point; there is a need for intergenerational contact.

 

In bees, the workers die young and the queens live a long time. We could try transplants on them.

How does bereavement status affect quality of life?

Julie Byles. For women, quality of life decreases with widowhood but recovers after a couple of years. They manage to reinvent their lives.

Should we take antioxidants before injury?

Zeinab Khalil. There are no studies examining the relationship between long-term intake of antioxidants and tissue repair. Long-term intake of exogenous antioxidants could depress our endogenous antioxidant defence system. It could alter the balance of the internal system.

Are the gender differences in life expectancy due to biological or environmental factors?

Julie Byles. I don’t know. The cliché is women get sick, men die. Women are the greatest users of the health care system. Women’s life expectancy may change as their lifestyles become more like men’s.

What is productive activity?

Julie Byles. Gardening, volunteer work, paid work. No one activity is linked to survival.

Is there telomerase in trees that live hundreds or thousands of years?

Roger Reddel. Those parts of plants that can be propagated long-term have telomerase activity, those parts that can’t be propagated don’t have telomerase.

Rob Helme. Jogging can extend your life by 2 years, but you’ll spend 2 years doing it. You have to
enjoy running.