Stroke is the third leading cause of death in the world. The incidence of stroke approximately doubles each decade after the age of 45, with a 2% annual risk over 80 years of age and a 3–7% annual risk over 95 years of age. Hypertension is also a major factor responsible for most deaths worldwide, nearly 50% more than cigarette smoking. The lifetime risk of developing hypertension is 90% in people surviving to 80–85 years of age.