Relationship of Retinal Vascular Fractal and Diabetes Mellitus in a Multi-Ethnic Asian Population in Singapore

Abstract

Purpose: : Diabetes mellitus has been suggested to have an impact on the retinal vasculature prior to the development of clinical signs of retinopathy. Previous studies have shown evidence of an association between retinal vascular caliber changes and diabetes. We now examined the association between diabetes and early geometric retinal vascular pattern using fractal analysis in a multi-ethnic population of Chinese, Malays and Indians in Singapore.

Methods: : This is a population-based case-control study utilizing data from the Singapore Prospective Study Program and the Singapore Cardiovascular Cohort Study 2. A total of 615 participants were analyzed with 270 cases that met the criteria for diabetes and 345 controls that were matched for age and gender. Diabetes was defined as fasting plasma glucose ≥7 mmol/L (≥ 126 mg/dL), self-reported physician diagnosed diabetes or the use of oral hypoglycaemic medication or insulin. Fractal dimension (D_f) was measured from retinal photographs of cases and controls using the International Imaging Software- Fractal (IRIS-Fractal) programme. Multivariate logistic regression models were used to determine the odds ratio (OR) and 95% confidence interval (CI) for diabetes in relation to D_f as a continuous or categorical variable (quintiles), adjusted for age and ethnicity, and subsequently for systolic blood pressure, body mass index, low-density lipoprotein (LDL) and alcohol consumption.

Results: : No significant association was seen between diabetes and D_f. The OR (95% CI) of diabetes associated with D_f was 1.15 (0.94- 1.39) adjusted for age and ethnicity and 1.10 (0.89- 1.35) with further adjustment for other factors. In stratified analysis by ethnicity (Chinese/ Malay/ Indian), significant results were seen in Chinese persons, with odds of diabetes significantly higher among persons with D_f in the 2^nd and 4^th quintiles as compared to the 3^rd quintile after adjusting for age. However, further multivariate analysis showed no significant association between diabetes and D_f.

Conclusions: : There was no association demonstrated between diabetes and retinal fractal dimension in this multi-ethnic population of Chinese, Malays and Indians in Singapore.

Keywords: retina • diabetes