Is insulin resistance or diabetes mellitus associated with stroke? An 18-year follow-up study

Insulin resistance and/or diabetes are risk factors for corollary artery di sease. However, it is still controversial whether they are associated with the development of stroke. A total of 304 Japanese men and women, aged 20-6 9 years, were selected on the basis of casual high blood glucose concentrat ions from 2732 participants of a population-based health examination in 198 0. They all underwent a 50 g oral glucose tolerance test in 1981. Homa IR ( index of insulin resistance) and Homa beta -cells (index of beta -cell func tion) were calculated from their fasting insulin and glucose using the form ulas for the homeostasis model. They were followed-up for 18 years. Inciden ce of stroke was investigated by computed tomography. During 18 years, 28 s ubjects had a stroke; 21 had ischemic and nine had hemorrhagic strokes (two had both). Baseline variables, which showed an independent association wit h the incidence of stroke in the Cox proportional hazard model, were blood pressure, use of anti-hypertensive medications, and Homa beta -cell index ( inversely) after adjustments for age and sex. After further adjustment for blood pressure using a step-forward method, Homa beta -cell was significant ly related to the incidence of stroke (Hazard ratio: 0.65, 95% confidence i nterval: 0.44-0.95). In addition to hypertension, diabetes but not insulin resistance, is a risk factor for stroke. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.