To examine geographic variation in the incidence of ischemic stroke (IS) and acute myocardial infarction (AMI) in Finland during 1991-2003.
Data included all cases of first IS (n = 115,383) and AMI (n = 205,213) in persons aged 35-84 years. We used full Bayesian spatial shared component disease models for mapping the geographic risk patterns.
The risk component shared by IS and AMI explained 73% (95% credible interval [CI]; 59%, 87%) of the geographic variation in IS risk and 68% (41%, 91%) in AMI risk. The spatial variation was similar in men and women. In the northeastern part of Finland, annual age-adjusted IS incidence was 356.4/100,000 (95% CI; 350.3, 362.6) in men and 231.2 (226.9, 235.4) in women. Annual AMI incidence was 855.6 (846.1, 865.2) in men and 351.4 (346.2, 356.5) in women. In the southwestern part of the country, annual IS incidence was 334.7 (331.6, 337.8) in men and 210.6 (208.5, 212.6) in women. Annual AMI incidence was 707.3 (702.8, 711.8) in men and 278.3 (276.0, 280.7) in women.
A marked part of the spatial variation in IS and AMI incidence was disease specific, even though these diseases share a similar atherosclerotic background. Further studies are warranted for understanding the reasons for the different geographic variation.