The word "stroke" evokes an image of something that just happens, like a stroke of bad luck. Indeed, there are unavoidable strokes related to age, family history, gender (at older ages women have more strokes than men), and certain diseases of the arteries. However up to 80% of strokes are completely preventable! Manageable risk factors include smoking, high blood pressure, diabetes, obesity, atrial fibrillation (an irregular heart rhythm), alcohol use, and high cholesterol.