AIM: To examine the association between high density lipoprotein(HDL)3 cholesterol, nitrite plus nitrate(NOx)and total antioxidant status in diabetic retinopathy patients compared to controls.

METHODS: This was a prospective, case-control study. One hundred and six participants were subdivided into three groups. Eighty-four type 2 diabetes patients with and without retinopathy and 22 healthy controls were included in this study. Serum HDL₃ concentrations were assayed and serum NOx levels were determined in all patients. Total antioxidant capacity was measured using the ferric reducing power of plasma(FRAP)assay.

RESULTS: Among the subjects with diabetes mellitus(DM), fasting glucose, HbA1c and triglycerides were significantly higher than the healthy controls. HDL₃ level was 14.4(12.0)mg/dl in healthy subjects, 18.1(12.6)mg/dl in the diabetic retinopathy group and 14.0(12.5)mg/dl in diabetic patients without retinopathy, and was statistically similar between the groups(P=0.262). HDL level was similar between groups in our population. FRAP level was lower in patients with DM compared to healthy controls(P=0.003), but was not different between the DR and the non-DR groups(P=0.913).

CONCLUSION: In our study, we demonstrated that HDL and HDL₃ subgroup levels didn't significantly differ between DM2 patients with DR and without DR and healthy controls. Determination of HDL₃ cholesterol, in addition to total HDL cholesterol, may not predict the actual risk for diabetic retinopathy. Serum NOx was observed to be higher in diabetic participants and FRAP level was low.