Changing pattern of cerebral infarction: 1945--1974.

This study has identified all persons in the population of Rochester, Minnesota, who had a diagnosis of cerebral infarction during the period Jan. 1, 1970, through Dec. 31, 1974, and has confirmed the continuing decline in the incidence rate previously reported. The decline in the rate has been accelerating, with a relatively greater reduction occurring in women and in the more elderly age groups. There has been a decline in the prevalence rate in women which was not seen in men. The over-all impact of cerebral infarction was to reduce the proportion of those persons who were completely independent from 57% before cerebral infarction to 16% after infarction. Comparison of survival among patients with cerebral infarction occurring in the two quinquennia 1945--49 and 1970--74 showed only a 2% increased probability of survival at 30 days; the difference in survival increased progressively to 16% at 5 years. The reason for the declining incidence and increased survival in cerebral infarction in this population has not been established, but evidence of increased community surveillance and treatment of hypertension among persons before the onset of cerebral infarction is presented.