Trick or Treatment by Simon Singh, Edzard Ernst M.D. Read Free Book Online Page A

consensus in sight, Hill teamed up with Doll and decided to investigate one of the proposed causes of lung cancer, namely smoking. However, they faced an obvious problem – they could not conduct a randomized clinical trial in this particular context. For instance, it would have been unethical, impractical and pointless to take 100 teenagers, persuade half of them to smoke for a week, and then look for signs of lung cancer.
    Instead, Hill and Doll decided that it would be necessary to devise a prospective cohort study or an observational study , which means that a group of healthy individuals is initially identified and then their subsequent health is monitored while they carry on their day-to-day lives. This is a much less interventionist approach than a randomized clinical trial, which is why a prospective cohort study is preferable for exploring long-term health issues.
    To spot any link between smoking and lung cancer in their prospective cohort study, Hill and Doll worked out that they would need to recruit volunteers who fulfilled three important criteria. First, the participants had to be established smokers or vehement non-smokers, because this increased the likelihood that the pattern of behaviour of any individual would continue throughout the study, which would last several years. Second, the participants had to be reliable and dedicated, inasmuch as they would have to commit to the project and submit regular updates on their health and smoking habits during the course of the prospective cohort study. Third, in order to control for other factors, it would help if all the participants were similar in terms of their backgrounds, income and working conditions. Also, the number of participants had to be large, possibly several thousand, because this would lead to more accurate conclusions.
    Finding a group of participants that met these demanding requirements was not a trivial task, but Hill eventually thought of a solution while playing golf. This prompted his friend Dr Wynne Griffith to comment, ‘I don’t know what kind of golfer he [is], but that was a stroke of genius.’ Hill’s brilliant idea was to use doctors as his guinea pigs. Doctors fitted the bill perfectly: there were lots of them, many were heavy smokers, they were perfectly able to monitor their health and report back, and they were a relatively homogenous subset of the population.
    When the smoking study commenced in 1951, the plan was to monitor more than 30,000 British doctors over the course of five decades, but a clear pattern was already emerging by 1954. There had been thirty-seven deaths from lung cancer and every single one of them was a smoker. As the data accumulated, the study implied that smoking increased the risk of lung cancer by a factor of twenty, and moreover it was linked to a range of other health problems, including heart attacks.
    The British Doctors Study, as it was known, was giving rise to such shocking results that some medical researchers were initially reluctant to accept the findings. Similarly, the cigarette industry questioned the research methodology, arguing that there must be a flaw in the way that the information was being gathered or analysed. Fortunately, British doctors were less sceptical about Hill and Doll’s emerging conclusions, because they themselves had been so involved in the study. Hence, they were not slow in advising the public against smoking.
    Because a link between cigarettes and lung cancer would affect smokers around the world, it was important that the work of Hill and Doll was replicated and checked. The results of another study, this time involving 190,000 Americans, were also announced in 1954, and the conclusion painted a similarly stark picture. Meanwhile, research with mice showed that half of them developed cancerous lesions when their skin was coated in the tarry liquid extracted from tobacco smoke, showing that cigarettes definitely contained carcinogens. The picture was completed