AIMS: The authors describe the occurrence of diabetes and obesity in the population of Northern Sweden and the role of diabetes in cardiovascular disease. METHODS: Four surveys of the population aged 25 to 64 years were undertaken during a 14-year time span. Stroke events in subjects 35-74 years during 1985-92 and myocardial infarction in subjects 25-64 years 1989-93 were registered. RESULTS: The prevalence of diagnosed diabetes was 3.1 and 2.0% in men and women, respectively, and 2.6 and 2.7% for previously undiagnosed diabetes. During the 13-year observation period, BMI increased 0.96 kg/m(2) in men and 0.87 in women. The proportion of subjects with obesity (BMI>or=30) increased from 10.3% to 14.6% in men and from 12.5% to 15.7% in women. Hip circumference increased substantially more than waist circumference, leading to a decreasing waits-to-hip ratio (WHR). The relative risk for stroke or myocardial infarction was four to six times higher in a person with diabetes than in those without diabetes. The 28-day case fatality for myocardial infarction, but not for stroke, was significantly higher in both men and women with diabetes. Population-attributable risk for diabetes and stroke was 18% in men and 22% in women and for myocardial infarction it was 11% in men and 17% in women. CONCLUSION: Obesity is becoming more common, although of a more distal than central distribution. The burden of diabetes in cardiovascular diseases in Northern Sweden is high.