Purpose: To determine the relationship between grade of diabetic retinopathy and serum vitamin D levels in diabetic patients.
Materials and methods: A total of 173 diabetic patients consisting of patients without retinopathy (n=67), patients with non proliferative diabetic retinopathy (NPDRP group n=47), patients with proliferative diabetic retinopathy (PDRP group n=59) was included in the study. Age and sex matched 55 healthy subjects was taken as a control group. Patients with type 1 DM, those taking vitamin D, multivitamin including vitamin D, drug affecting vitamin D metabolism like rifampin, phenytoine was excluded from the study. Patients with chronic renal failure was also excluded. Dilated fundoscopic examination of all subject was done and serum creatinine, HbA1c, 25 hydroxy vitamin D (25 (OH) D) level of all subject were measured between May 2012 and September 2012.
Result: There was no statistical difference in age, sex, systolic tension, diastolic tension and BMI between groups. Serum creatinine level was also not statistically different between groups (P=0.11). The mean 25 (OH)D levels of PDRP group, NPDRP group, diabetic patients without retinopathy and control group was 11.9±6.4, 18.8±10.2, 16.6±7.5 and 20.1±9.2 ng/ml respectively. There was statistically significant difference between PDRP group and other groups in univariate analysis (P<0.001). When comparing 173 diabetic patients, regardless of retinopathy, with control group, 25 (OH) D levels was significantly lower in diabetic patients than control group (P=0.004).
Conclusion: Diabetic patients especially, patients with proliferative diabetic retinopathy had lower serum vitamin D level than healthy subjects. Additionally randomised, controlled, prospective studies are necessary to determine whether vitamin D treatment will stop or slow the progression of diabetic retinopathy in diabetic patients.
16 - 20 May 2015
European Society of Endocrinology