Inter-Relations between Dietary Patterns and Glycemic Control-Related Biomarkers on Risk of Retinopathy in Type 2 Diabetes.

Diabetic retinopathy (DR), which can cause vision loss, may progress faster with poor glycemic control and oxidative stress. This study aims to examine how dietary patterns and glycemic control biomarkers relate to retinopathy risk in type 2 diabetes patients. In this study, we enrolled diabetic patients with retinopathy (DR) ( n = 136) and without retinopathy (no DR) ( n = 466) from a cohort of participants in the "Blood Pressure Control to Reduce the Risk of Type 2 Diabetic Nephropathy Study". Hemoglobin A1c (HbA1c) and malondialdehyde were defined as elevated when their levels reached ≥8.5% and ≥2/3 (16.2 μm), respectively. Dietary data were collected by a food frequency questionnaire. Dietary patterns were identified by factor analysis. Elevated HbA1c was significantly correlated with increased risk of DR (OR: 2.12, 95% CI: 1.14-3.93, p = 0.017). In subjects with a high animal protein and processed food dietary pattern (≥highest tertile score) or a low vegetable intake pattern (<highest tertile score), elevated HbA1c was significantly associated with a 4.44-fold (95% CI: 1.34-14.68, p = 0.015), 3.96-fold (95% CI: 1.12-14.04, p = 0.033), and 2.57-fold (95% CI: 1.16-5.67, p = 0.020) increase in the risk of DR, respectively, compared to subjects with HbA1c levels < 8.5%. When stratifying subjects with a high animal protein pattern, higher MDA levels were significantly correlated with an increased risk of DR (OR: 2.93, 95% CI: 1.33-6.48, p = 0.008). Poor glycemic control increases the risk of retinopathy in patients with type 2 diabetes, and combined with diets low in vegetables and high in animal protein or processed food may exacerbate the risk of DR. The findings of this study should be further investigated in prospective studies.