General risk factors

Many of the same clinical variables associated with atherosclerotic vascular disease, especially CHD are also associated with an increased risk for ischemic stroke. Several observational studies have reported a relationship of increased stroke risk and traditional CHD risk factors. However, the studies do not demonstrate that risk factors for CHD are consistently risk factors for stroke. In the large evaluation of 450000 subjects from 45 prospective observational, cohort studies with 5-30 years of follow-up (total: 7.3 million person-years of observation), after adjustment for age, there was a relationship of increased stroke risk with blood pressure, but not for blood cholesterol (8). Diabetes was not reported in this study.
The Framingham Heart Study demonstrated that in men and women there is a relationship to blood pressure, diabetes, cigarette smoking as well as the presence of cardiovascular disease, and that these variables were additive in their contribution to stroke risk (1). Men who participated in The Honolulu Heart study and Framingham Study were recently compared by Rodriguez et al. (9). They demonstrated that although event rates were different in these 2 study populations, hypertension, cigarette smoking, diabetes and obesity (determined by body mass index) were associated with increased stroke risk.
There has not been a consistent relationship between serum cholesterol levels and stroke risk in observational studies. This topic has recently been reviewed by Amarenco (10) who noted that there was no association found between cholesterol levels and stroke risk in the Framingham study while there was a relationship between total cholesterol and stroke risk reported in the MRFIT study (11). The large combined analysis done by the Prospective Studies Collaboration could not show a relationship between cholesterol concentrations and stroke risk in 45000 subjects with a total of more than 7 million years of patient follow up (8).