Declining incidence and mortality rates of stroke in Finland from 1972 to 1991. Results of three population-based stroke registers.

Abstract

We aimed to determine trends in stroke incidence, mortality rates, case-fatality rates, and their relation in Finland. We compared the results of three population-based stroke registers that included first-ever strokes in people aged > or = 15 years. Two registers were kept in Espoo-Kauniainen, the first in 1972 to 1973 (EK 72-73) and the second in 1978 to 1980 (EK 78-80). The present register of the Finnish Heart Association (FHA 89-91) was kept in four districts in Finland in 1989 to 1991. The age-adjusted incidence rates were 240.9, 174.4, and 191.6, and the 1-year mortality rates were 121.9, 77.0, and 65.3 in the EK 72-73, EK 78-80, and FHA 89-91 registers, respectively. The overall decline from 1972 to 1991 was 20% in the stroke incidence rate and 46% in the stroke mortality rate. One-month case-fatality rates decreased from 34.8% to 29.4% in the EK 72-73 and EK 78-80 registers and to 23.3% in the present register. The decline in the stroke incidence rate during the 1970s stabilized during the late 1980s and early 1990s; however, the case-fatality rate is still decreasing. Their combined effects may explain the continuing decline in stroke mortality.