Cardiovascular risk factors and the effects of intervention. Cardiovascular risk factors can be substantially modified by changes in life-style such as diet, exercise, smoking cessation, and moderation of alcohol consumption. In turn, these can reduce blood pressure, heart rate at rest, and blood lipid concentrations. Epidemiologic evidence shows that for every 1% change in serum cholesterol levels, there is a 3% change in the likelihood of developing coronary heart disease. In addition, a long-term (5-year) change of 5 to 6 mm Hg in diastolic blood pressure can reduce the chances of stroke by 35 to 40% and of coronary heart disease by 20 to 25%. The full impact of this broad range of interventions on population health has still to be fully realized in many countries, including the United Kingdom, however it is likely to be considerable. Some of the recent evidence in support of such cardiovascular risk factor modification is selectively reviewed. 