Abstract
Background: Emerging data from in vivo and in vitro investigations have proven that Vitamin D deficiency may be a risk factor for the etiology of diabetes and its consequences; however, individual published studies have yielded conflicting results. The current study’s goal was to evaluate and correlate Vitamin D levels in the blood of diabetic patients with and without diabetic retinopathy (DR), as well as to correlate Vitamin D with duration of diabetes, age and HbA1C.

Aim and Objectives: The aim of the study was to evaluate and correlate Vitamin D levels in the blood of diabetic patients with and without DR, and to correlate Vitamin D levels with age, duration of diabetes, and HbA1C.

Materials and Methods: A cross-sectional case-control study of 150 Type 2 diabetes mellitus (T2DM) patients (aged 35–70 years) was included. The 150 Type 2 Diabetic patients were separated into three groups: Group 1 (no DR, n = 52), Group 2 (non-proliferative DR [NPDR], n = 58), and Group 3 (PDR, n = 42). Enrolled participants were subjected to a thorough physical examination to rule out the occurrence of microvascular problems, which included microfilament testing and a thorough fundus examination. Serum samples were used to test fasting blood sugar, HbA1C, and serum Vitamin D.

Results: T2DM subjects with DR had lower mean serum 25 (OH) D concentrations than patients without DR (21.5 ± 9.5 vs. 17.7 ± 10.2 vs. 14.4 ± 5.9; P = 0.04). Mean HbA1C concentration was significantly lower in No DR (NDR) in comparison to NPDR and PDR (7.6 ± 1.5; vs. 8.5 ± 1.9; vs. 9.3 ± 1.8; P = 0.037. In addition, there was a significant negative correlation between the blood 25 (OH) D level and age (–0.165; P = 0.015), diabetes duration (–0.172; P = 0.014), and HbA1C (–0.148; P = 0.040).

Conclusion: The current investigation showed that patients with DR have lower levels of 25 [OH] D than those with non DR subjects. 25 [OH] D levels were negatively associated with age, duration of diabetes, and HbA1C.