Context: The relation between endothelial dysfunction (ED), glycemic control, and early type I diabetes mellitus (T1DM) is unclear.
Objective: The objective of the study was to evaluate the association of ED, glycemic control, and the duration of diabetes in T1DM.
Design: This was a cross-sectional study.
Setting: The study was conducted at a public outpatient clinic.
Patients: Fifty-seven T1DM adolescents and 10 healthy age-matched controls participated in the study.
Intervention: There were no interventions.
Methods and outcome measures: Endothelial function (ED) was evaluated by flow-mediated dilation (FMD) in the brachial artery after reactive hyperemia. Biochemical data, including HbA1c (glycohemoglobin), high-sensitivity C-reactive protein, lipids, and urinary albumin excretion were collected. Means of four HbA1c values collected at 3-month intervals in the first and second year before FMD analyses were obtained.
Results: Mean FMD was decreased in T1DM compared with controls (P = 0.023), independent of age, smoking, hypertension, or dyslipidemia. Twenty-eight of 57 T1DM patients enrolled (49%) had ED. FMD was decreased in microalbuminuric (4.1%) compared with normoalbuminuric patients (10.1%, P = 0.01) and controls (14.6%, P < 0.001). FMD correlated inversely with mean second-year HbA1c (r = -0.426, P = 0.02), particularly in patients with less than 5 yr of T1DM (r = -0.61, P = 0.004). In these patients, high-sensitivity C-reactive protein was strongly correlated with mean first-year HbA1c (r = -0.66, P = 0.0003). In patients with more than 5 yr of T1DM, we found no significant correlations between ED and glycemic control.
Conclusions: Endothelial dysfunction is common in T1DM adolescents with less than 5 yr of disease. It is associated with duration of disease, microalbuminuria, and mean second-year HbA1c but not with mean first-year HbA1c. These data support the metabolic memory hypothesis.