Materials and Methods: Eighty six patients with type II Diabetes Mellitus and 22 age and sex matched healthy subjects were enrolled in the study. The diabetic patients were divided into four groups according to stage of retinopathy. All groups were also divided into two subgroups as patients taking oral antidiabetic drugs (OAD) or patients who taking insulin treatment. In all groups, body mass index was calculated, fasting serum leptin levels were measured and mean values between groups were statistically evaluated.

Results: There were no statistically significant differences between groups with respect to age, body mass index, systolic and diastolic blood pressure, serum HbA1C, and total cholesterol levels. Proliferative diabetic retinopathy (PDR) group had significantly higher leptin levels among the retinopathy groups (background diabetic retinopathy, p: 0.018; preproliferative diabetic retinopathy, p: 0.033). The mean serum leptin level was 19.6±11.3 ng/ml in the control group and 42.5±22.7 ng/ml in the PDR group. The difference in leptin levels between two groups was statistically significant (0.006). When comparing the subgroups, OAD subgroup had significantly higher leptin levels compared to insulin subgroup in the PDR group (p:0.037). Although leptin levels were lower in the insulin subgroups compared to OAD subgroups in other retinopathy groups, differences were not statistically significant.

Conclusion: While serum leptin levels were significantly higher in patient with PDR, its levels in patients with non-proliferative retinopathy or without retinopathy did not show significant difference when comparede with the control group. It seems that the serum leptin levels are lower in patients taking insulin treatment. Keywords : Leptin, Serum levels, Diabetes Mellitus, Retinopathy