Abstract
PURPOSE: Diabetic retinopathy (DR) is a prevalent microvascular complication of type 2 diabetes mellitus (T2DM). Current research indicates that the association between Vitamin D and diabetic retinopathy, particularly in the early stages, remains controversial. Therefore, we conducted this research to explore the correlation between vitamin D levels and microvascular alterations in nonproliferative diabetic retinopathy (NPDR) patients utilizing optical coherence tomography angiography (OCTA). PATIENTS AND METHODS: A cross-sectional analysis was conducted on 286 eyes from 150 subjects with NPDR, with or without diabetic retinopathy. All participants underwent OCTA examinations to assess retinal vessel density (VD), foveal avascular zone (FAZ) area, and retinal thickness. The relationships between vitamin D levels and OCTA-derived parameters were analyzed through multiple regression analyses. RESULTS: Our analysis revealed a notable decline in retinal vessel density linked to vitamin D deficiency. The superficial vascular complex and the deep vascular complex exhibited reduced vessel density associated with lower vitamin D levels. Additionally, an increase in parathyroid hormone levels significantly correlated with an enlargement of the FAZ area. Vitamin D deficiency was an independent factor in retinal microvascular pathology in T2DM, as evaluated by OCTA. CONCLUSION: Individuals with T2DM and vitamin D deficiency were highly recommended to undergo regular ophthalmic screenings to monitor retinal health.