Because there is so much concern about the provision of medical care, both in the rich industrialised countries and in the developing world, this is a particularly opportune time for the association to be looking at the many ways in which science can be used for improving our health, the theme of this year's meeting.
The World Health Organisation's dream of 'health for all by the year 2000' has long faded. While a fifth of the world's people can look forward to living in reasonable health well into their late seventies, one-third is still suffering from avoidable illness and premature death. Fifteen million children are dying each year from infections and malnutrition, and 500,000 women are lost from the consequences of childbirth. And even in the richer nations, the whole ethos of modern medicine is being questioned.
It is argued that medical science, with its reductionist approach and emphasis on established disease, has done little to control non-infectious killers. Rather, it has bred hi-tech, patch-up medicine that is bankrupting society and losing sight of the needs of patients. There is a growing belief that many problem diseases are the result of our environments and lifestyles. Perhaps we already know enough about their causes to control many of them; all that is needed is more efficient and cost-effective provision of health care, and a greater emphasis on a healthy life and preventive medicine.
Much of this new way of thinking about medical care stems from the successes of the epidemiologists in relating some forms of cancer and heart disease to cigarette smoking. But it is vital that this work, important though it is, should not lead us into a false sense of security. The role of other aspects of our lifestyles that have been implicated as causes of heart disease and cancer is much less clear, and we have no idea whether environmental culprits are involved in problem diseases such as rheumatism, high blood pressure, mental illness and dementia, for example. Neither should we forget that genetic disease is one of the major causes of death and chronic ill-health in children and young adults.
If we are not to put all our medical eggs into the environmental basket, what are the alternatives? As in the past, we will have to pin our hopes on the medical sciences. And here we seem to be in a stronger position than before to come to grips with some of our most troubling diseases.
Developments over recent years in the basic biological sciences, particularly molecular and cell biology, offer us, for the first time, the opportunity to understand the causes and mechanisms of many of our intractable diseases and the chance to control some of the important problems of the developing world, particularly the population explosion and the infectious and parasitic diseases that continue to decimate large populations. Some of this work, particularly where it involves genetic manipulation, may raise ethical issues. There is nothing new in this; it is difficult to think of any major medical advance over the centuries that did not do so.
There is a mood of scepticism and unease about the goings on in the molecular sciences, and fears about what scientists may be getting up to as they meddle with our genes. This also stems from increasing impatience and frustration; rarely a week goes by without another breakthrough being announced by our scientists and yet, so far, few appear to have made much impact in the clinic.
When, in March 1882, Robert Koch announced the discovery of the germ that caused tuberculosis, it was hailed by the press as the answer to the disease that was killing one in every five of the population. In the event, it was another 70 years before work in the basic sciences, leading to the discovery of streptomycin and related drugs, saw the end of tuberculosis as a major killer - at least in the richer countries. Because most of today's problem diseases have multiple causes, they are much more complex than tuberculosis. Last week's 'gene for cancer' and this week's 'gene for Alzheimer's disease' are important stepping stones, but we should not expect them to lead to the control of these diseases overnight.
If adequately supported, the medical sciences offer enormous possibilities for our future well-being. In the short term they can help us to evolve better methods for the provision of health care in the community and for assessing the validity and outcome of current clinical practice. And if we are willing to take a long-term view, the basic biological sciences offer the best hope of a genuine understanding of our intractable killers and for controlling them.
But these are extremely complex issues. It is vital that scientists join both government and the public in a debate about the direction of the scientific exploration of health care; government needs to understand the best way to use its limited resources and the rest of us need to know how to evaluate the conflicting advice we are receiving on how to improve our health.
Equally important, we must all take part in a wider discussion on the ethical issues arising at the interface of science and medicine. With its wide coverage of so many aspects of the medical sciences, this week's meeting is an ideal forum to encourage this dialogue.
The writer is Regius Professor of Medicine at the University of Oxford.