Coronary heart disease is the major cause of morbidity and mortality in industrialised countries. The Framingham cohort study has identified the quantitative impact of different risk factors and their interactions,1^–3 and large intervention studies have confirmed that drug treatment to reduce risk factors decreases progression to heart attack and stroke.4 5 However, with this increased understanding have come additional problems. The treatments to reduce cholesterol concentrations or blood pressure are often expensive, and the population that might benefit is vast. Indeed if every individual who might benefit was treated with a statin or fibrate, a large portion of the total drugs budget would be consumed.6 Thus some form of rationing is inevitable, and various recommendations have emerged in an attempt to contain cost while targeting treatment at those who stand to gain the most. Current UK policy recommends treatment should be offered to anyone with an absolute annual risk of 3% or more.7 Others, however, favour a 1.5%-2% absolute threshold before beginning treatment, 8 9 and some have argued that estimates of relative risk should form the basis for treatment guidelines.10 Since age is the major determinant of absolute risk, treatment thresholds based on absolute risk will tend to postpone treatment to older age, whereas guidelines based on relative risk will tend to lead to treatment of younger people.