Protective Role of Vitamin D Supplementation in Proliferative Diabetic Retinopathy in a Type 1 Diabetes Premenopausal Woman: A Case Report from the region of Dobrogea, Romania.

Objectives: To present the case of a premenopausal woman with long-standing type 1 diabetes mellitus and diabetic retinopathy, in whom severe vitamin D deficiency was associated with poor metabolic control and depressive symptoms, and whose ocular and systemic condition spectacularly improved after vitamin D supplementation. Material and methods: We describe the clinical history, laboratory findings, and ophthalmological assessments of a 42-year-old woman from an urban area of Dobrogea, Romania. The patient had a 28-year history of type 1 diabetes mellitus complicated with proliferative diabetic retinopathy, early-stage chronic kidney disease, and diabetic polyneuropathy. Initial laboratory evaluation indicated severe vitamin D deficiency (8 ng/mL), marked glycemic variability (documented by continuous glucose monitoring), and microalbuminuria. Results: Following six months of vitamin D supplementation, serum levels increased to 40 ng/mL, depressive symptoms improved, and the patient became more adherent to nutritional therapy. Ophthalmological follow-up: Optical Coherence Tomography (OCT) retinal findings showed stabilization of retinal neovascularization. Discussion: The distinctiveness of this case arises from the coexistence of multiple risk factors, including long-duration type 1 diabetes with microvascular involvement, pronounced vitamin D deficiency despite favorable sun exposure conditions, premenopausal status under HRT, and retinal changes objectively documented before and after supplementation. Conclusions: This case supports the hypothesis that vitamin D may have a protective role against retinal neovascularization in diabetic retinopathy, possibly by reducing inflammation and angiogenesis trend, and indirectly by improving metabolic control.