The Bad News:
If you have a genetic pre-disposition to hypertension, high cholesterol problems, or diabetes, your chances of having a stroke are greatly increased.

The Good News:
The causes of stroke and heart attack have been identified and can be decreased through regular doctor visits and good health patterns.

How to Stay Healthy and Stroke-Free
Avoid smoking and second-hand smoke
Make sure your diet includes a variety of fruits, vegetables, grains, low-fat or non-fat dairy products, fish, legumes, poultry, and lean meats.  
Avoid saturated fats, cholesterol, and trans-fatty acids. 
Limit alcohol consumption to 2 drinks a day per day for men, 1 drink for women. 
Engage in at least 30 minutes of moderate-intensity physical activity four to five days per week.
Stay slim (BMI should be 18.5-24.9).
Take a low dose aspirin often

When and what stroke risk factors you should get screened for 
The American Heart Association recommends beginning screenings for stroke risk factors at age 20 and assessing smoking status, diet, alcohol intake, and physical activity level should annually.  It’s also recommended that blood pressure, weight/body mass index (BMI), waist circumference, and pulse (to screen for atrial fibrillation) be recorded every two years, while a  fasting cholesterol profile and fasting blood sugar should be checked every 2-5 years depending on each person's personal risk assessment.

For further information, refer to: "AHA Guidelines for Primary Prevention of Cardiovascular Disease and Stroke: 2002 Update," Pearson, T MD PhD; Blair, S PED; Daniels, S MD PhD; Eckel R MD; Fair, J RN PhD; Fortmann, S MD; Franklin, B PhD; Goldstein, L MD; Greenland P MD; Grundy, S MD PhD; Hong, Y MD PhD; Miller, N RN; Lauer, R MD; Ockene, I MD; Sacco, R MD MS; Sallis, J  Jr PhD; Smith, S Jr MD; Stone, N MD; Taubert, K PhD, Circulation, vol 101, 2002.