Retinal Arteriolar Narrowing Predicts Incidence of Diabetes: The Australian Diabetes, Obesity and Lifestyle (AusDiab) Study

Abstract

Objective: To examine the relationship of retinal vascular caliber to incident diabetes in a population-based cohort.

Research Design and Methods: The Australian Diabetes, Obesity and Lifestyle Study recruited adults aged 25+ years across Australia in 1999-2000, with a follow up 5 years later in 2004-2005. Participants' glycemic status was classified using fasting plasma glucose (FPG) and 2-hour oral glucose tolerance (2hPG) tests. Diabetes was diagnosed if FPG ≥7.0 mmol/l or 2hPG ≥11.1mmol/l. Retinal vascular caliber was measured from baseline retinal photographs using a computer-assisted program.

Results: Of the 803 participants without diabetes at baseline, 108 (13.4%) developed diabetes at follow up: 7 (2.8%) from 246 participants with normal glucose tolerance, 9 (13.6%) from 66 participants with impaired fasting glucose, and 92 (18.7%) from 491 participants with impaired glucose tolerance. After multivariate analysis, participants with narrower retinal arteriolar caliber had higher risk of diabetes (odds ratio 2.21, 95% confidence interval 1.02-4.80, comparing smallest vs. highest arteriolar caliber tertiles, p=0.04 for trend). There was no association between retinal venular caliber and incident diabetes.

Conclusions: Narrower retinal arteriolar caliber predicted risk of diabetes. These data provide further evidence that microvascular changes may contribute to the pathogenesis of diabetes.