Epidemiology

Although stroke incidence increases exponentially with age from about 40, Framingham data confirm that the attributable risk from hypertension falls after 60, from a relative risk of 3.5 then, to statistically indistinguishable from 1 in the 80s.3 In a study of over 4000 ambulatory hypertensive patients over the age of 80 years, mortality was higher in the 5-year follow-up period in those with lower systolic and diastolic blood pressure (BP).4 Epidemiological evidence shows little effect of cholesterol on stroke risk.5 Data from 61 prospective observational studies yielded nearly 12 million person-years at risk between the ages of 40 and 89 years. The risk for ischaemic heart disease death, for any given level of cholesterol, fell with age and in participants over 70 years (and particularly for those with systolic BP over about 145 mm Hg) total cholesterol was negatively related …