Risk factors in stroke.

In the United States, stroke accounts for 160,000 annual deaths; only 16% of the 1.8 million stroke survivors are fully independent. The incidence of stroke increases with age. Hemorrhagic strokes outnumber ischemic strokes before age 15. Japanese men in this country have a lower stroke mortality than their age peers in Japan. Excessive stroke mortality for US nonwhites may not be entirely due to the greater prevalence of hypertension among blacks. Hypertension emerges as the single most powerful and reversible risk factor in stroke and for survival after stroke. Impaired cardiac function is the second most important precursor of stroke. The recurrence of stroke in survivors is high. The frequency of completed stroke is high in persons with transient ischemic attacks, but not in those with asymptomatic carotid bruits. Other reversible risk factors are smoking, the use of oral contraceptives, alcoholic excess, a low level of physical activity, blood hyperviscosity and drug abuse.