In the United States, there are 600,000 new or recurrent strokes each year, according to statistics from the American Heart Association. Stroke is the third leading cause of death. It is also the main cause of long-term disability in the United States, with 4.6 million stroke survivors alive today.

Established risk factors for stroke include standard risk factors that lead to the development of cardiovascular disease. Cigarette smoking elevates risk of ischemic stroke by as much as 90%. Smoking cessation can result in a marked reduction in stroke risk.

Hypertension at least doubles risk of stroke, and it is undertreated in Western countries. 27% of Americans have hypertension. Only 23% reach goal levels through treatment. Drug treatment of hypertension can reduce stroke mortality by as much as 45%, regardless of other risk factors.

Diabetes increases stroke risk by 40% to 70%. Unfortunately, several randomized studies do not show that glucose control can reduce that risk. However, diabetics have an increased prevalence of risk factors. In the Heart Outcomes Prevention Evaluation (HOPE) study, diabetics who received ramipril for blood pressure control had a 33% reduction in stroke risk.

Atrial fibrillation is an important risk factor for stroke in the elderly. A meta-analysis suggests that warfarin reduces risk of stroke by 61% in atrial fibrillation patients.

Total cholesterol is presumed to be a stroke risk factor. In a meta-analysis of 18 studies and other cohorts, total cholesterol was neither protective nor deleterious to risk of stroke. However, this was for all types of stroke. In the Multiple Risk Factor Intervention Trial (MRFIT), there was an inverse association between total cholesterol and hemorrhagic stroke. On the other hand, individuals with high total cholesterol had the highest risk of ischemic stroke.

Western researchers are increasingly using subclinical disease markers to risk-stratify patients. For example, the Framingham Heart Study looked at the inflammatory marker C-reactive protein (CRP) and found a dose-response relationship. Higher CRP correlated with higher risk of stroke at follow-up. For the highest CRP quartile, risk had approximately doubled.

There are a number of important differences in stroke epidemiology between East and West. For example, in China, the rate of hemorrhagic stroke is up to 30% compared with 15% in the West. Lacunar ischemia is more prevalent in the East, while atherothrombotic ischemia is more common in the West. Smoking is on the rise as a risk factor in the East, while diabetes is increasing in the West.

However, there are more similarities than differences. Stroke shares common antecedents and are largely due to modifiable risk factors. It is often preventable. Importantly, both West and East underutilize risk factor modifications such as smoking cessation that could profoundly reduce the incidence of this disease.