Lipoprotein(a) (Lp(a)) is an independent risk factor for cardiovascular diseases in non-diabetic people, but few studies have been done in diabetic patients. To investigate whether Lp(a) is a risk factor for cardiovascular disease in elderly people with diabetes, we examined the association of Lp(a) and serum lipid levels (total cholesterol: TC; triglycerides: TG; and high-density lipoprotein cholesterol: HDL-c) with the incidence of coronary artery disease and cerebrovascular disease. We studied 354 outpatients(131 men and 223 women, 60-97 years of age) with non-insulin-dependent diabetes mellitus. The mean concentration of Lp(a) was 21.1 +/- 19.6 mg/dl and the median was 14.0 mg/dl. The Lp(a) concentration did not correlate significantly with age or with sex, but it did correlate significantly with TC (r = 0.152, p < 0.05) and with the level of apoprotein B (r = 0.168, p < 0.05). The incidence of cerebrovascular disease was significantly higher in patients with high concentrations of Lp(a) (> or = 30 mg/ dl) than in those with low concentrations (< 30 mg/ dl). Multivariate logistic regression analysis revealed that male sex, hypertension, a high level of HbA1c, a low level of HDL, and a high level of Lp(a) were independent risk factors for cerebrovascular disease. The incidence of coronary artery disease tended to the higher in those with high concentrations of Lp(a) (> or = 30 mg/dl). However, multivariate logistic regression analysis revealed no significant correlation between Lp(a) concentration and the incidence of coronary artery disease. We conclude that a high concentration of Lp(a) is an independent risk factor for cerebrovascular disease in elderly patients with diabetes.