Hyperinsulinemia and the risk of stroke in healthy middle-aged men: the 22-year follow-up results of the Helsinki Policemen Study.

BACKGROUND AND PURPOSE Several studies have shown that hyperinsulinemia is associated with the risk of coronary heart disease, but information on the association of hyperinsulinemia with the risk of stroke is limited. We investigated the association of hyperinsulinemia with the risk of stroke during a 22-year follow-up of the Helsinki Policemen Study population. METHODS The study was based on a cohort of 970 men aged 34 to 64 years who were free of cerebrovascular disease, other cardiovascular disease, or diabetes. Risk factor measurements at baseline examination included an oral glucose tolerance test with blood glucose and plasma insulin measurements at 0, 1, and 2 hours. Area under the insulin response curve during oral glucose tolerance test was used as a composite variable reflecting plasma insulin levels. RESULTS During the 22-year follow-up, 70 men had a fatal or nonfatal stroke. Hyperinsulinemia (highest area under the insulin response curve quintile compared with the combined 4 lower quintiles) was associated with the risk of stroke (age-adjusted hazard ratio, 2.12; 95% CI, 1.28 to 3.49), but not independently of other risk factors (multiple-adjusted hazard ratio, 1.54; 95% CI, 0.90 to 2.62), which was mainly due to the impact of obesity, particularly upper body obesity, with subscapular skinfold thickness used as an index. Of other risk factors, upper body obesity, blood pressure, and smoking were independent predictors of the risk of stroke. CONCLUSIONS Hyperinsulinemia was associated with the risk of stroke in Helsinki policemen during the 22-year follow-up, but not independently of other risk factors, particularly upper body obesity.