Retinal Vascular Caliber and Diabetes in a Multiethnic Asian Population

Objective: The aim of this study was to examine the relationship of retinal vascular caliber with diabetes and impaired fasting glucose (IFG) in a multiethnic Asian population.

Methods: This work was a population-based cross-sectional study comprising 3,404 Singaporean Chinese, Indian, and Malay participants. Retinal arteriolar and venular diameters, CRAE and CRVE, respectively were measured from digital retinal photographs. Diabetes was defined as physician-diagnosis of diabetes, self-reported use of diabetic medication, or fasting plasma glucose (FPG) ≥ 7 mmol/L; IFG as FPG 6.1–6.9 mmol/L.

Results: After adjusting for age, gender, ethnicity, systolic blood pressure, body mass index, total cholesterol, triglycerides, smoking, and vascular caliber (Model 3), participants with diabetes had both larger CRAE and CRVE, compared to those with normal fasting glucose (NFG) or IFG. In a multivariate analysis, including clinical risk factors and CRVE, mean CRAE increased from 143.6 μm in NFG to 145.3 μm with diabetes (P for trend = 0.01). On the other hand, each mmol/L increase in FPG was associated with a 0.51-μm increase in CRVE (P=0.006). In a subgroup analysis stratified by ethnicity, the association between FPG and larger CRVE was predominantly present among ethnic Indians (0.9-μm increase in CRVE per mmol/L increase in FPG).

Conclusion: Diabetes was associated with larger retinal arteriolar diameters and glucose level was associated with larger retinal venular diameters in this multiethnic Asian population. The magnitude of association between glucose level and venular widening was stronger among ethnic Indians.