The most important thing about stroke: prevention
by Don B. Smith, M.D., Director, Colorado Neurological Institute Stroke Program

Stroke is a leading cause of death and disability throughout the world. In the United States more than 700,000 strokes each year give rise to staggering financial and emotional burdens. This unfortunate situation is made more regrettable by the fact that many, perhaps most strokes, are preventable.

Many things contribute to the occurrence of stroke, and avoiding a stroke is largely a matter of identifying and reducing risk factors. Some risk factors such as age, gender and race, are not amenable to modification — but many other risk factors are modifiable. Some of these have been known for several decades, while others have been recognized only recently.

Long-recognized risks include high blood pressure, heart disease (especially heart attack and heart arrhythmia, such as atrial fibrillation), diabetes, high cholesterol, carotid artery disease and smoking. By some estimates nearly half of all strokes could be prevented if we would just do just three things: 1) Control all cases of high blood pressure; 2) Convince all smokers to stop; 3) Use appropriate treatment in all patients with atrial fibrillation. Additionally, there is good evidence that treatment of high cholesterol and carotid artery disease can further reduce the risk of stroke.

While the classical risk factors noted above account for the majority of strokes, a substantial minority of patients—perhaps one-third—have none of these classical risks. In recent years we have discovered additional risks, many of them modifiable. These are briefly summarized here.

While lack of physical exercise increases stroke risk, regular physical exercise, as simple as walking for 20 minutes three times a week, can reduce the risk of stroke and the risk of premature death or heart disease.

Diet influences stroke risk. Higher intake of sodium is associated with increased risk. Replacing saturated fats with unsaturated fats reduces risk. Fruits and vegetables may be protective because of antioxidant mechanisms or elevation of potassium levels. Vitamins C and E, along with beta-carotene, are associated with stroke risk reduction. Inadequate intake of vitamin B-12, pyridoxine, and folic acid may contribute to stroke risk by raising homocysteine levels. Heavy alcohol use (more than four drinks per day) is a stroke risk factor, while moderate alcohol use (one to two drinks a day) seems to be protective.

Among the more surprising stroke risks are some infections, especially those involving chlamydia, cytomegalovirus and periodontal disease. Inflammatory markers (elevated erythrocyte sedimentation rate or elevated C-reactive protein) also predict stroke risk, as do antibodies against cellular components such as phospholipids.

Finally, we are learning that many genetic factors influence stroke risk. Among these factors are variations (polymorphisms) of lipoprotein (a), blood clotting factors V and II, protein C, protein S, antithrombin III, fibrinogen, apolipoprotein E, alpha 2-adrenergic receptor, endothelial NOS, lipoprotein lipase, methylenetetrahydrofolate reductase, plasminogen activator inhibitor promoter, platelet glycoprotein IIIa, platelet-activating factor, renin and angiotensin.

The explosion of information about stroke risk offers many opportunities for intervention and prevention, but stroke risk assessment is a complex matter. We are proud that at the Colorado Neurological Institute, in collaboration with colleagues on the National Stroke Association’s Stroke Prevention Advisory Board, we have recently created a computer-based tool for quantitative measurement of stroke risk. We anticipate that this tool, the Stroke Risk Disk, will improve the awareness of stroke risk factors and the accuracy of stroke prediction. In so doing, we hope that it will also lessen the impact of stroke for everyone.

The Colorado Neurological Institute (CNI) is the largest, most comprehensive neuroscience center in the Rocky Mountain region.

CNI coordinates integrated, multi-disciplinary teams of neuroscientists who provide comprehensive care for adults and children suffering from a wide range of neurological disease. Programs include exciting new research and treatments for stroke, Parkinson’s disease, Huntington’s disease, epilepsy, brain tumors, spinal cord injuries, head trauma, hearing disorders, sleep disorders, migraines, ALS, and many other disorders.