domingo, 2 de dezembro de 2007

Os precursores da epidemiologia moderna

Abaixo, os comentários de MichaelMarmot publicados no The Lancet sobre o livro mostrado ao lado.
When I joined Epidemiology at the London School of Hygiene and Tropical Medicine, in 1976, I was told: this School is run by upper-class Englishmen and lower-class Scotsmen—my informant was a Scotsman. He went on: it reflected the old Colonial Medical Service; the Englishmen went to the tropics to run the empire, and the Scots to escape their lousy weather. In the USA, I had been told, it was surprising how many of the older generation of epidemiologists had a father who was a preacher, or were of Jewish background. It reflected their social concern. Of course, the London School has Hygiene as well as Tropical Medicine in its title and there were motivations, other than noblesse oblige or the weather, that brought people into epidemiology. One of the attractions of The Development of Modern Epidemiology is the insight it gives into these motivations. It brings together contributions from many who have been centrally involved in the International Epidemiology Association (IEA) during the 50 years of its existence. So many of the key figures came to epidemiology because they wanted to improve health in society. John Pemberton, the co-founder of the IEA, was a member of the Socialist Medical Association that was started in 1930. Many of their members believed that poverty was an important cause of ill-health and that some solutions to health problems required political action. In the same vein, Mervyn Susser was aroused to hope and commitment to a socially useful occupation. He, and Zena Stein, saw the practice of socially oriented medicine as an important form of activism. As always, such commitment does not arise, prosper, or otherwise in a vacuum. The pioneers of this approach in South Africa, among them Sydney Kark, as well as Susser and Stein, had to leave because they fell foul of the political regime promoting apartheid. Jerry Morris, in the UK, stated it clearly: “Society largely determines health; ill-health is not a personal misfortune due often to personal inadequacy but a social misfortune due, more commonly, to social mismanagement and social failure.” The commitment to improving health for the whole of society runs through many of the contributions in this volume. Ian Prior's great grandfather was a missionary in Fiji whose public-health contribution was to convince his parishioners to give up cannibalism. Henry Blackburn, the master of the ECG in epidemiology, was influenced by experiences in Cuba, in 1949, that taught him of the limitations of medicine to deal with mass disease due mainly to poverty and ignorance. Lester Breslow, slightly coy, says that friendly advice was that “with my ideology, I consider public health”. Public Health is grateful that he heeded this advice. I am in awe of these pioneers. Today, rightly, we expect our students to do Master's degrees and PhDs, to get accredited, pass exams. That is as it should be. But it does not stop me worshipping at the shrine of these founders of our discipline who had none of these qualifications. It may be social concern that motivated these pioneers of epidemiology, but they brought methodological rigour to their enquiries and they had to make it up as they went along. Richard Doll, in a characteristically pithy piece, does not suggest that he chose to go into “epidemiology” as such. Rather, he used his mathematical bent to help a distinguished clinician, Avery Jones, to investigate variations in the occurrence of peptic ulcer. A short course in medical statistics with Bradford Hill (what, no PhD!) and he was put to work to figure out why lung cancer was on the rise. He reports that there were a few early case-control studies of cancer that had come in for methodological criticism. Doll and Hill, therefore, designed their case-control study of lung cancer and smoking to be better. They published in 1950, concluding, with no messy understatement or qualification: “that cigarette smoking is an important cause of cancer of the lung”. The pioneers developed their investigations with rigour and, in part because of shortage of funds, with precision. Archie Cochrane is justly famous for effectiveness and efficiency and has been immortalised in the Cochrane collaboration. He also did so much to develop observational epidemiology. Nearly 30 years ago I made a pilgrimage to south Wales to see Archie at work, then in his 80s. He drove me in his little car out into the Rhondda where he was still following a cohort of miners. We called on a miner's cottage and a woman took a death certificate off the mantelpiece with the words that her husband had died 3 years previously and she kept the certificate because she knew that Professor Cochrane would call. We then drove back to Cardiff. “That's it”, I asked, “just the death certificate, no questionnaire to the widow?” “What would you want to ask?”, said Archie, “I got all the information I needed.” Archie Cochrane's personal contribution sums up another theme running through the volume: the different uses of epidemiology, to borrow Jerry Morris' 1957 phrase. Breslow and Detels are clear: epidemiology is the basic science of public health. Richard Heller and Kerr White are equally clear: epidemiology can be used to improve clinical practice and the evaluation and, hence, operation of health services. When we discover that some non-infectious diseases are infectious in origin it makes clear that there should not be two epidemiologies—infectious and non-infectious. There is surprisingly little whingeing in this volume. There is the occasional allusion to sneering reactions from the medical establishment to the pursuit of epidemiology. These pioneers cannot have had it easy, yet they focus on getting the job done rather than dwelling on their critics. Richard Doll says simply: “epidemiology has contributed more than any other branch of science to our knowledge of the causes of cancer”. There is some allusion to the political nature of a concern with the health of populations. Adapting this to contemporary debates, a critic, exercising his prejudices, might read the accounts by John Pemberton and others of their social concerns and see not a group motivated by the highest ideals but a bunch of do-gooders who are out to provide ammunition to the nanny state to control people's lives. Rodolfo Saracci puts this another way. In a thoughtful chapter he suggests that, in the period 1945–75, the rise in epidemiology reflected the impulse of postwar reconstruction and a sense of social solidarity. Accepting health as the right of everybody meant that epidemiology with its focus on whole populations had a ready political acceptance and results had some chance of influencing policy. At the start of the millennium, says Saracci, a neoliberal climate will pay more attention to economics than to a political desire to improve the lot of all sectors of society. Saracci's implications are plain: we need high-quality epidemiological research and we need the political commitment to implement findings to improve population health. In: Walter W Holland, Jørn Olsen and Charles du V Florey, Editors, The Development of Modern Epidemiology: Personal Reports From Those Who Were There, Oxford University Press (2007) ISBN 0-19856-954-8 Pp 472. US$110·00

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