Box 15.1 Just because screening should work doesn't mean it will!

In the 1960s, public health practitioners were seduced by the concept of early diagnosis – give people regular health checks to identify and treat disease early. It seemed so obvious it would work that initiatives of this type started springing up in the USA and UK. The UK Ministry of Health realised that the implications were enormous, so between 1967 and 1976 a trial was conducted in London to evaluate the benefits of multiphasic screening of middle-aged adults in general practice. Approximately 7,000 participants were randomly allocated to receive two screening checks two years apart or no screening and all participants then underwent a health survey. The investigators did not find any significant differences between the two groups in terms of their morbidity, hospital admissions, absence from work for sickness or mortality. The only outcome appeared to be the increased costs of health-care – approximately £142 million to screen the entire middle-aged UK population (and that was at 1976 prices). (The South-East London Screening Study Group, 1977; reprinted in 2001 with a series of commentaries, Various, 2001.)