Is there any correlation between vitamin D insufficiency and diabetic retinopathy?

AIM

To determine a relation between vitamin D level, which is an inhibitor of angiogenesis, and diabetic retinopathy and its risk factors.

METHODS

In a clinic-based cross sectional study two hundred and thirty-five type 2 diabetic patients older than 20y were selected. Patients were classified according to ophthalmologic examination as following: no diabetic retinopathy (NDR) (n=153), non-proliferative diabetic retinopathy (NPDR) (n=64) and proliferative diabetic retinopathy (PDR) (n=18). Study subjects were tested for fasting blood glucose, glycated hemoglobin A1C (HbA1C), lipid profile, microalbuminuria, HsCRP, IGF1, insulin (in patients without history of insulin taking) and 25 hydroxy vitamin D [25 (OH) D] levels. Vitamin D insufficiency was defined according to 25 (OH) D level less than 30 ng/mL. The relationship between diabetic retinopathy and serum 25 (OH) D insufficiency was evaluated.

RESULTS

The prevalence of diabetic retinopathy was 34.8% in our patients. Long duration of diabetes, hypertension, poor glycemic control, diabetic nephropathy, hyperinsulinemia and insulin resistance were risk factors for diabetic retinopathy but 25 (OH) D level was not significant different between NDR, NPDR and PDR groups. Correlation between 25 (OH) D level and other known risk factors of diabetic retinopathy was not significant.

CONCLUSION

This study did not find any association between diabetic retinopathy and its severity and vitamin D insufficiency. Vitamin D insufficiency is not related to risk factors of diabetic retinopathy.