Abstract

Objective: Alterations in retinal vascular caliber may reflect early subclinical microvascular dysfunction. In this study, we examined the association of retinal vascular caliber to incident retinopathy in young people with type 1 diabetes.

Research Design and Methods: A prospective cohort study of 645 initially retinopathy-free type 1 diabetic patients, aged 12 to 20 years. Participants had 7-field stereoscopic retinal photographs taken of both eyes at baseline and follow-up. Retinal vascular caliber was measured from baseline photographs using a computer-based program following a standardized protocol. Incident retinopathy was graded according to the modified Airlie House classification from follow-up photographs.

Results: Over a median follow-up of 2.5 years, 274 participants developed retinopathy (14.8/100-person-years). After adjusting for age, gender, diabetes duration, glycemia, systolic blood pressure, body mass index and cholesterol levels, larger retinal arteriolar caliber (fourth versus first quartile) was associated with more than three-fold higher risk of retinopathy (hazard rate ratio [HR] 3.44; 95% confidence interval [CI]: 2.08, 5.66). Each standard deviation increase in retinal arteriolar caliber was associated with 46% increase in retinopathy risk (HR 1.46, 95%CI: 1.22, 1.74). This association was stronger in female than in male participants. After similar adjustments, retinal venular caliber was not associated with incident retinopathy.

Conclusions: Retinal arteriolar dilatation predicts retinopathy development in young people with type 1 diabetes. Our data suggest that arteriolar dysfunction may play a critical role in the pathogenesis of early diabetic retinopathy and that computer-based retinal vascular caliber measurements may provide additional prognostic information regarding risk of diabetic microvascular complications.