The value of preventive medicine. Screening in adults

Controversy over cervical cytology prompted the setting of guidelines for the provision of a screening service. These are discussed in terms of the relationship between blood pressure and cerebrovascular disease and the relationship between the blood cholesterol level and ischaemic heart disease. In the first case, concern mainly centres on the level of blood pressure at which treatment should be started and the effectiveness of treatment. In the second case, a currently active controversy is whether intervention by dietary methods should be directed towards the whole community or only towards those at particularly high risk. The economic issues are illustrated by reference to a detailed theoretical study of the cost-effectiveness of four options for the prevention of ischaemic heart disease, based on action starting in childhood.