The importance of cholesterol, blood pressure and smoking for coronary heart disease

See doi:10.1016/S1095-668X(03)00471-8 for the article to which this editorial refers Worldwide cardiovascular diseases account for half of all deaths in middle age (and considerable additional disability) and one third of all deaths in old age. Most of these deaths involve ischaemic heart disease (IHD) or stroke. Epidemiological studies carried out over the last half century have shown that cigarette smoking, elevated blood pressure and dyslipidaemia increase the risk of cardiovascular diseases and randomized trials have shown that lowering blood pressure and cholesterol prevents cardiovascular disease. Nevertheless, there are popular misconceptions about the relative importance of these classical risk factors, including the widely held belief that they only account for about half of all cardiovascular diseases.1The underestimation of the importance of these risk factors has arisen from analyses of prospective cohort studies in which measurements of blood pressure or cholesterol recorded on enrolment to the study (the ‘baseline’ survey) were related to subsequent risk of developing IHD. But, due to the combined effects of measurement errors, short-term biological variability and longer-term systematic changes within individuals, baseline measurements often do not reliably indicate the long-term average, or ‘usual’, level of a risk factor either at around the time of the baseline measurement or during a later …