Is vitamin D deficiency associated with retinopathy in type 2 diabetes mellitus? A case-control study.

BACKGROUND AND AIMS: This study aimed to determine the associations between vitamin D deficiency and diabetic retinopathy (DR) progression risk in type 2 diabetes mellitus (T2DM) patients.

METHODS: This is a case-control study that enrolled 201 diabetic retinopathy (DR) patients as case and 201 T2DM without DR as a control. Demographic variables were obtained during an interview using a questionnaire, furthermore, anthropometric measures were evaluated based on the standard protocol. In addition, biochemical indices including 25-hydroxyvitamin D, fasting blood glucose (FBG), insulin, Glycosylated hemoglobin (HbA1c), total cholesterol (TC), LDL-C, HDL-C, and triglyceride (TG) were assessed for all of the participants. Multivariate logistic regression was performed to estimate the relationship between vitamin D and retinopathy.

RESULTS: Based on the statistical analysis of age, sex, and BMI there was no significant difference between the two groups, while the mean concentration of 25-hydroxyvitamin D substantially was lower in case group in comparison with the control group (14.46 VS. 19.88). Furthermore, low levels of vitamin D are associated with DR and consequently proliferative diabetic retinopathy (PDR) in patients with T2DM.

CONCLUSION: Totally based on the results of the present study vitamin D deficiency increased the risk of RD in patients with T2DM, also in case of deficiency of this nutrient, retinopathy may develop into PDR type.