Lewis A. Conner Lecture. Contributions of epidemiology to the prevention of stroke.

E pidemiological study and clinical trial research has flourished during the past 40 years. During this period the decline in death rates from stroke in the United States has accelerated. Since 1970 the US stroke mortality rate has declined nearly 60%. There is reason to believe the declining death rate is related to improvements in the risk factor status of the US population.