Trends in Mortality, Morbidity, and Risk Factor Levels for Stroke From 1960 Through 1990: The Minnesota Heart Survey

Objective.—The Minnesota Heart Survey is a population-based study designed to monitor and explain trends in cardiovascular mortality, morbidity, and risk factors. Design.—Surveillance time-trends study. Methods.—The following trends were examined among men and women aged 25 to 74 years living in Minneapolis—St Paul, Minn: (1) stroke mortality from 1960 through 1990; (2) risk factors in population-based surveys conducted in 1973 through 1974, 1980 through 1982, and 1985 through 1987; and (3) morbidity in a 50% sample of hospitalized discharges for acute-stroke in 1970, 1980, and 1985. Results.—Stroke mortality in Minneapolis—St Paul declined slowly from 1960 through 1972 (average fall, 2.4% per year), dropped sharply from 1972 through 1984 (average fall, 6.5% per year), but exhibited little change thereafter (average fall, 1.5% per year). The average level of cardiovascular disease risk factors fell from 1973-1974 to 1985-1987, with the exception of body mass index. In particular, hypertension diagnosis, treatment, and control levels improved substantially between 1973-1974 and 1980-1982, although there was little improvement after 1980-1982. While discharge rates for hospital-coded acute stroke declined substantially between 1970 and 1985 in both sexes, no clear trend was observed in definite stroke rates as validated using standard clinical criteria. Twenty-eight—day case fatality rates of definite stroke improved significantly from 1970 to 1985. Conclusions.—The substantial decline in stroke mortality of more than 50% from 1960 through 1990 appears to have been attributable to both primary and secondary prevention. These data suggest that the long decline in stroke mortality and morbidity in Minneapolis—St Paul has plateaued, although improved detection of stroke with computed tomography prevents an unequivocal conclusion.