Serum levels of Leptin and Adiponectin are associated with diabetic retinopathy in an Asian population with diabetes mellitus.

Abstract

Purpose: To investigate the relationship between serum levels of the adipokines (leptin and adiponectin) with diabetic retinopathy (DR) in Asian subjects with diabetes mellitus.

Methods: A nested case-control study selecting cases with DR and controls without DR from 2 large population-based cohorts, namely the Singapore Chinese Eye Study and the Singapore Indian Eye Study. All subjects had a comprehensive eye examination and blood and urine samples were collected at baseline . Diabetes was defined as casual plasma glucose ≥200mg/dl (11.1mmol/l), glycosylated hemoglobin (HbA1c) levels ≥6.5%, self-reported physician-diagnosed diabetes, or the use of glucose lowering medication. 327 controls with diabetes and no DR and 158 cases with DR were randomly selected and their serum was sent for the measurement of leptin and adiponectin levels. Retinal photographs, taken from both eyes, were graded for the presence and severity of DR using the modified Airlie House classification system.

Results: The mean±SD serum leptin and adiponectin levels were 14.3±16.3 ng/l and 8.6 ± 4.8ug/l, respectively. Patients with DR had higher mean serum leptin (19.2±22.5 versus 12.0±11.6 ng/l, p<0.001) and adiponectin values (10.0±7.0 versus 7.9±2.9 ug/l, p<0.001) compared to those without DR . In multivariate logistic regression models adjusted for age, gender, body mass index, HbA1c, systolic blood pressure and duration of diabetes, higher serum leptin (OR [odds ratio] 2.14 per SD, 95%CI [confidence intervals]: 1.52-3.00, p<0.001) and adiponectin (OR 1.92 per SD, 95%CI: 1.38-2.65, p<0.001) were associated with an increased risk of any DR. Further adjustment for ethnicity and use of medications such as angiotensin receptor blockers or angiotensin-converting enzyme inhibitors did not alter the association.

Conclusions: Higher serum leptin and adiponectin levels are associated with diabetic retinopathy independent of other known risk factors. Altered regulation of adipokines may play a role in the pathogenesis of diabetic retinopathy.

Keywords: 499 diabetic retinopathy • 464 clinical (human) or epidemiologic studies: risk factor assessment • 490 cytokines/chemokines