['To determine whether arterial compliance of patients with type 1 diabetes is reduced before the development of clinically apparent diabetes complications.', 'Pulse-wave analysis was used to compare vascular compliance between patients with type 1 diabetes and nondiabetic control subjects. Analysis of covariance was used to determine differences between the two groups with adjustment for age if needed.', 'A total of 59 patients with type 1 diabetes were studied; age ranged from 17-61 years. Of the 59 patients, 32 had no evidence of diabetes complications and 27 had microvascular complications. The control group consisted of 57 healthy subjects ranging in age from 23-79 years. In the control group, large artery compliance (C1) and small artery compliance (C2) were inversely proportional to age (r = -0.55 for C1 and -0.50 for C2; P < 0.01). When the control subjects were compared with type 1 diabetic patients without microvascular complications, C1 was 1.51 +/- 0.04 (SEM) for the control group and 1.33 +/- 0.06 (SE) ml/mmHg for the diabetic group, whereas C2 was 0.080 +/- 0.005 (SE) and 0.065 +/- 0.005 (SE) ml/mmHg for the control and diabetic subjects, respectively, when adjusted for age (P = 0.03 for both C1 and C2).'] Is vascular compliance reduced in the early stages of type 1 diabetes?