Plasma homocysteine is associated with nonproliferative retinopathy in patients with type 2 diabetes without renal disease

Background and aimsThis study aimed to assess the role of plasma homocysteine (Hcy) in the development of nonproliferative diabetic retinopathy (NPDR) in patients with type 2 diabetes (T2DM) without chronic kidney disease.MethodsThis was a cross-sectional study that included 94 T2DM. Hcy, serum 25-hydroxy (25-OH) vitamin D, vitamin B12, and folate were determined by the CMIA method. NPDR was determined according to the EURODIAB retinal photography methodology and optical coherence tomography (OCT) of the macula.ResultsCompared to patients without NPDR, patients with NPDR had longer diabetes duration (p < 0.001), higher Hcy (p < 0.001), lower vitamin B12 (p = 0.028) and lower estimated glomerular filtration rate (eGFR) (p = 0.004). NPDR was positively associated with diabetes duration (p < 0.001), HbA₁c (p = 0.049) and Hcy (p < 0.001), and negatively with vitamin B12 (p = 0.027) and eGFR (p = 0.005). Logistic regression analyses showed that diabetes duration (OR = 1.13, p < 0.001), Hcy (OR = 1.06, p = 0.047), and eGFR (OR = 0.96, p = 0.004) were the main predictors of NPDR in T2DM. Stepwise regression analyses showed that the best model for predicting Hcy (R2 = 0.104) included vitamins B12 and D.ConclusionsHigher Hcy is associated with NPDR and may play a role as a risk factor for its development in T2DM. Vitamins B12 and D seem to modify this association.