Abstract
Purpose::
To examine the relationship of retinal vascular caliber to diabetes, glycemic status and diabetic retinopathy (DR).
Methods::
The Australian Diabetes, Obesity and Lifestyle Study (AusDiab, 1999-2000) recruited adults aged 25+ years from 42 randomly selected areas nationwide. Diabetes was defined as fasting plasma glucose (FPG) ≥7.0 mmol/l or 2-hour plasma glucose (2HPG) level ≥11.1 mmol/l. Impaired glucose tolerance (IGT), impaired fasting glucose (IFG) and normal glucose tolerance (NGT) was further defined from the FPG and 2HPG values. Non-mydriatic, digital retinal photographs were taken of 2,476 participants and graded for DR. Retinal vascular caliber was measured by computer-assisted methods.
Results::
Of the 2020 people with gradable retinal images, KDM was present in 16%, NDM in 17%, IGT in 42% and IFG in 6%. Retinal arteriolar caliber (RAC) was significantly larger in KDM (179µm) compared to NGT (175µm) (p=0.02) after adjusting for age, gender, systolic blood pressure, body mass index, alcohol, smoking, HDL cholesterol and triglycerides. Each standard deviation (SD) increase in RAC was associated with increased odds of having KDM compared to NGT (odds ratio, OR 1.24; 95%CI 1.04 - 1.47); and of having diabetes and mild-to-moderate non-proliferative DR compared to NGT with no DR (OR 1.59 95%CI 1.21-2.07). The association of larger RAC with KDM remained significant after further adjusting for venular caliber (p<0.05). In similar adjusted models, retinal venular caliber (RVC) was not significantly associated with glucose tolerance status, but was significantly associated with DR. Each SD increase in RVC was associated with an increased likelihood of having diabetes and mild-to-moderate non-proliferative DR (OR 1.77, 95% CI 1.34-2.32); this association remained significant after adjusting for RAC (p<0.05).
Conclusions::
Wider RAC was associated with known diabetes, and wider RVC was independently associated with DR.
Keywords: diabetic retinopathy • retina • clinical (human) or epidemiologic studies: outcomes/complications