The Rise and Fall of Modern Medicine (49 page)

Similarly, it is possible to dismiss the allegation that the electromagnetic fields created by electricity pylons might cause leukaemia, as the strength of the field generated by the pylons is hundreds of times less than Earth's static magnetic field to which everyone is exposed every day.
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It is an astonishing fact that not one of the numerous allegations of environmental threats to health of the last twenty years has ever been convincingly validated, for the simple reason that they are all crucified on the one single biological fact that the
scale of exposure is far below the threshold that could have physical effects on the human organism. The last word belongs to Aaron Wildavsky, author of much the most thorough and balanced analysis on this subject in recent years,
But is it True?.
And is it true? ‘Of all the subjects I have studied in over thirty years as a social scientist, environmental issues are the most extraordinary in that there is so little truth in them.'
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And so we return again to the early 1980s, when The Social Theory seemed to offer so much. The Age of Optimism in scientific medicine was over, there was a Dearth of New Drugs, the clinical scientist was an Endangered Species and suddenly The New Genetics and The Social Theory emerged to provide an entirely new direction where the causes of disease would be elucidated in the interplay between the external world – people's social habits and their environment – and their genes. This opened up a whole new range of opportunities, where social engineering would eliminate the common causes of death, while genetic manipulation would fix everything else.

In 1980 the promise of The New Genetics still lay in the future, but there was already more than enough known about the social causes of disease for action to be taken. And how easy it had turned out to be. Thirty years had elapsed since Sir Austin Bradford Hill had identified tobacco as the cause of lung cancer and now, in hardly any time at all, the other major pieces of the jigsaw had fallen into place. The ‘Western diet' was relatively high in fat and salt and low in dietary fibre, and chemical pollutants in the air and water were incriminated as a cause of most common illnesses – heart disease, stroke and many cancers. As time passed the links between everyday life and disease became ever clearer, as further investigations revealed many more previously unsuspected hazards. Alcohol was linked with cancer of the breast, coffee with cancer of the pancreas, yoghurt with cancer of the ovary, vaginal douching with cancer of the cervix, regular use of alcohol mouthwash with cancer of the mouth,
and red meat with cancer of the colon. Even the most innocent-seeming of inanimate objects, such as electricity pylons, mobile telephones and sewing machines, were all found to be full of menace.

But was any of it true? These hazards of everyday life might be a bit exaggerated but there can be no smoke without fire and so, one has to presume, they must contain an element of truth – as indeed there is. It is self-evident that those who live ‘sensibly' – eating and drinking in moderation, abjuring smoking and taking regular exercise – are likely to be healthier and fitter than those who do not, and thus more likely to live out their natural lifespan. But The Social Theory, as has been noted, claimed much more than this – that the Western diet and chemical pollutants are the specific preventable causes of certain illnesses – and yet its central tenets either ignore or are contradicted by the inescapable laws of biology. The dietary theory of heart disease and strokes is invalidated by the biological imperative of maintaining the ‘
milieu intérieur
' so the important physiological functions such as the levels of cholesterol and blood pressure are kept in ‘a steady state'. The dietary theory of cancer is invalidated by the contribution of biologically inevitable ageing to this age-determined disease. The environmentalist theory is invalidated by the biological necessity that the human organism be resilient and not readily injured by minuscule levels of pollutants in air and water. Still, the façade of knowledge The Social Theory presents to the world appears so impressive that, before accepting its incompatibility with the laws of biology, it is necessary to understand a little more of the science that underpins it – epidemiology – which, back in the 1940s, Sir Austin Bradford Hill had hoped would function as medicine's intellectual spring cleaner, dusting and hoovering away fallacious theories and treatments.

We start with the observation, already alluded to, that the post-war success of medicine was essentially empirical and technological, so that by the late 1970s therapeutic possibilities had been transformed, but medical science knew little more about what caused common diseases such as multiple sclerosis, diabetes and heart disease than forty years previously. This seeming inscrutability of the origins of disease extends to other phenomena, such as why they rise and fall over time and why they are common in some countries but rare in others. The one medical discipline most concerned with explaining these phenomena is epidemiology, which however is constrained in its search for the causes of disease by only being able to measure that which is measurable in people's lives. It cannot, by definition, discover hitherto unknown biological phenomena, such as the new bacterium, helicobacter, implicated in peptic ulcer, even though the pattern of the illness over the past 100 years strongly pointed to the possibility that peptic ulcer must have an infectious cause. Put another way, epidemiologists can only find the causes of disease in everyday life; and if the cause is not a factor of everyday life (but, say, a bacterium) then their explanation will be incorrect. Put a third way, most common diseases are either determined by ageing or caused by some unknown biological factor; hence the explanations that epidemiology provides are likely to be pseudo-explanations.

Nonetheless, epidemiological studies are easy to perform – take one group of people with a disease, another without, compare their lives and any differences can then be plausibly implicated as ‘the cause' – and thus rapidly filled the vacuum of ignorance. But, the associations that emerge from these studies are likely to be weak and contradictory, to the considerable confusion of the public. And, argued Professor Alvin Feinstein, editor of the
Journal of Clinical Epidemiology
, a scientific discipline
that generates such conflicting findings (coffee does, or does not, cause bladder cancer or congenital defects or heart disease; alcohol does, or does not, cause breast cancer; keeping pets is, or is not, associated with multiple sclerosis, and so on) can hardly be considered ‘scientific' at all, as its methods of investigation must be so clearly unreliable. ‘In other branches of science substantial distress would be evoked by a conflicting result . . . authorities would clamour for special conferences or workshops intended to identify the [methodological] defect and to institute suitable repairs. No such conferences and no such workshops have occurred.' Professor Feinstein's inside observations are so important as to merit elaboration. A scientist in any serious discipline, such as genetics, would be in serious trouble if his fellow scientists were unable to confirm or replicate his claim to have found, say, the gene for fatness. He would gain a reputation as being ‘unreliable' and universities would be reluctant to employ him. This self-imposed insistence on rigorous methodology is missing from contemporary epidemiology; indeed the most striking feature is the insouciance with which epidemiologists announce their findings, as if they do not expect anybody to take them seriously. It would, after all, be a very serious matter if drinking alcohol really
did
cause breast cancer.
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In parallel with this lack of internal scrutiny, there is the problem of external scrutiny by others who might ask questions about the apparent inconsistencies of their explanations. It is at this point that epidemiologists resorted (wittingly or not) to deceit to sustain their argument, by presenting only the highly selected version of evidence that appeared to substantiate their case. And then they retired behind the closed doors of the committee room, where, under the guise of examining the entrails of scientific evidence they could compile their reports – from
which so many important facts were simply omitted. Their motivation was simple enough – they had no alternative. The Social Theory was, by the 1980s, very influential. Its protagonists were powerful men and women who had spent enormous sums of state and charitable funds to prove their theories, so their admission of error could destroy their reputations. They did not even seem to acknowledge they might have been mistaken, but believed so passionately in the veracity of their theories that any minor blemish – such as negative results in the heart disease trials – could be brushed aside.

This collective self-delusion is not common and suggests the protagonists, in constructing their façade of knowledge, must in some way have been different from the mainstream of medicine. They were – being motivated by a shared set of ideological beliefs that might tactfully be described as ‘idealist utopianism'. They had a much grander, nobler vision than ordinary doctors in the surgery who spent their time treating the sick. They aspired to nothing less than the prevention of illness on a massive scale. There is nothing wrong with wanting to make the world a better place, but utopianism has its dangers. It presupposes a greater knowledge base than medicine possesses, while at the same time it refuses to recognise the possibility of uncertainty – that some things might be unknown.

Utopians entranced by ‘big' ideas tend to be dismissive of small details that get in the way. They are forever producing plans and setting targets for how people should change their dietary habits, but have no model of human action, no understanding of how people do change. Thus the cardinal feature of The Social Theorists is a lack of insight. With their eyes firmly fixed on the horizon and absolutely convinced of the rightness of their cause (and bolstered by their own personal sense of moral worthiness in pursuing it), they fail to appreciate that their
understanding of disease is limited to the statistics that appear on their computer screens. It is theoretical rather than practical, so they miss out on the sobering experience of testing their theories against reality. It only takes contact with a few real patients with heart disease to appreciate that their dietary habits are no different from anyone else's. It only takes a short period as a family doctor to recognise how extraordinarily difficult it can be to get people to stop smoking, hence a public health strategy that requires doctors to encourage their patients to make substantial changes in what they eat – even if it were proven to be beneficial – is condemned by its own impracticality.

This utopian impracticality is epitomised by Sir Geoffrey Rose of the London School of Hygiene and Tropical Medicine, the most prominent epidemiologist in Britain in the 1980s and already encountered as the organiser, under the auspices of the World Health Organisation, of the enormous trial involving tens of thousands of men in factories across Europe, in which intense efforts to encourage them to switch to a ‘healthy lifestyle' had no effect on their subsequent risk of heart disease. This should have been a setback, but Professor Rose realised, after reflection, that the fault lay not in the theory but in the ‘strategy' for preventing heart disease. It would be much better, he argued, rather than trying to get those with markedly elevated cholesterol levels to make substantial changes in the amount of fat they consumed, to try to persuade everyone to make small reductions. This became known as the ‘population strategy' as it was directed, typically ambitiously, at the whole population. This concept might be difficult to grasp but is easier to understand in relation to another problem deemed suitable for the population strategy – preventing the harmful effects of heavy drinking. Within any society there will be a typical distribution of alcohol consumption, with a minority being teetotallers, most people
drinking moderate amounts and at the other extreme another minority of heavy drinkers. Professor Rose's strategy requires that the moderate drinkers should slightly reduce their alcohol consumption, say by one glass of wine a day. This theoretically would shift the distribution of the pattern of alcohol consumption downwards, so that there would be fewer heavy drinkers at the top, thus reducing the problems associated with alcoholism. It sounds, and indeed is, a completely fantastical notion, but even more so when applied to preventing heart disease, as encouraging everyone to make small dietary changes has absolutely no effect on cholesterol levels. And yet, astonishingly, Geoffrey Rose's ‘Big Idea', as it became known (without any ironic appreciation that ‘Big Ideas' are precisely epidemiology's problem), now forms the basis of official health education policy, justifying the advice to everyone to change their lives in minute particulars. This disconnectedness from the real world illustrates how readily epidemiologists could come to believe in anything, even their own theories.
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This did not prevent The Social Theory from being very popular. It certainly caught the zeitgeist of the times, plugging into the ethos of self-improvement associated with the re-emergence of free-market economics, which was readily translated into the pursuit of personal physical fitness and accounted for the surge in popularity of jogging and marathons, of being slim, not smoking and eating a ‘healthy' diet. And it was highly plausible. It exploited the powerful imagery where fat furred up the arteries and salt overloaded the circulation; it provided, in the concept of the Diseases of Affluence, an explanation for the paradox that while everyone was becoming generally more prosperous and the standards of living ever higher, people still died. It seemed self-evident that life must have become too easy, as people could now afford to eat more than was good for them
and drive around in cars instead of walk. Necessarily, they must pay the consequences. The wonder of it was that it was all so simple, simple enough indeed to be encapsulated in a few powerful soundbites on television. It was certainly much easier to insist that ‘the modern British diet is killing people in their thousands from heart attacks' than to explain the complexities of why it is difficult to influence the cholesterol level in the blood by changing what one eats and, even if one were to make the effort, the evidence from the major trials showed that it conferred no benefit in protecting against heart disease. Finally, there was no ready way for others to test whether the claims of The Social Theory might be correct. When a surgeon introduces a new operation, only for others to find it does not work, it falls into disrepute. But how could one tell whether the process of social engineering was actually preventing common diseases? If, for some unknown reason, the rate of heart disease started to fall, the Social Theorists were only too happy to accept the credit but if, as in other instances such as cancer, there was no change, this was only evidence that not enough money was being spent on health promotion or that their efforts to promote change were being set aside.