Geographic Distribution of Stroke Incidence Within an Urban Population

Abstract

Background and Purpose —Geographic differences in stroke incidence indicate a potential for prevention. The present study from the city of Malmö, Sweden, sought to investigate whether incidence of stroke in residential areas is related to prevalence of cardiovascular risk factors and socioeconomic circumstances. Methods —The Stroke Register in Malmö, Sweden, was used for retrieval of the 3540 patients who suffered a first stroke between 1989 and 1998. The Malmö Diet and Cancer cohort (n=28 466) was used to assess area specific prevalence of hypertension, diabetes, smoking, and being overweight and for computation of a cardiovascular risk score. Socioeconomic circumstances for the 17 administrative areas were expressed in terms of a composite score. Results —Standardized stroke incidence ranged among areas from 437 to 743 per 100 000 for men and from 223 to 518 per 100 000 for women. Socioeconomic score correlated significantly with area-specific stroke rates among men ( r =−0.62, P =0.008) and women ( r =−0.67, P =0.004). Incidence of stroke was significantly associated with cardiovascular risk score for each area (men, r =0.53, P <0.05; women, r =0.76, P <0.001). The cardiovascular score and the socioeconomic score together accounted for 44% of the geographic variance among men and 63% among women. Conclusions —Marked differences occurred in stroke incidence among residential areas within this urban population. High-rate areas were characterized by a higher prevalence of smoking, hypertension, diabetes, and being overweight and by inferior socioeconomic circumstances. These risk factors accounted for a substantial proportion of the geographic variance in incidence of stroke.