Type 2 diabetes is not a risk factor for asymptomatic ischemic brain lesion--the Funagata study.

OBJECTIVE The purpose of this study is to clarify whether type 2 diabetes (DM) is a risk factor for asymptomatic (silent) ischemic brain lesion, which is controversial at present. SUBJECTS AND METHODS The subjects (n=187), who showed normal results on both neurological and neuropsychological examinations, underwent a 75-g OGTT and were examined by brain MRI on T1-weighted, T2-weighted, and FLAIR (fluid-attenuated inversion recovery) images. Their brain MRIs were evaluated quantitatively with the ischemia rating scale defined here. The subjects were grouped based on their glucose tolerance: normal glucose tolerance (NGT) (n=48), impaired glucose tolerance (IGT) (n=62), and DM (n=65). The subjects with DM were further divided based on their duration of illness: 20 with short duration (short DM: 1.3+0.8 years) and 45 with long duration (long DM; 8.9+/-5.4 years). Ages were matched among the groups. RESULTS The percentages of individuals with asymptomatic ischemic brain lesion were 81% in NGT, 74% in IGT, 65% in short DM, and 78% in long DM. No significant difference was observed among the groups in terms of the percentage. Namely, even in individuals with a long history of DM without clinical stroke, the prevalence of asymptomatic ischemic brain lesion was not different from that of the other groups. Multiple regression and multiple logistic regression analyses showed that age and hypertension were significant independent risk factors for asymptomatic ischemic brain lesion, whereas hypercholesterolemia, smoking, and glucose intolerance, including IGT, short DM and long DM, were not. CONCLUSION DM is not a risk factor for asymptomatic ischemic brain lesion.