Vitamin D deficiency increases the risk of retinopathy in Chinese patients with type 2 diabetes.

Abstract

To investigate the relationship between vitaminD deficiency and diabetic retinopathy. In total, 1520 patients with Type2 diabetes were recruited and divided into three groups according to their fundus oculi results: no diabetic retinopathy (n=625, 41.12%); non-sight-threatening diabetic retinopathy (n=562, 36.97%); and sight-threatening diabetic retinopathy (n=333, 21.91%). VitaminD deficiency was defined as a serum circulating 25-hydroxyvitaminD level <20ng/ml. Clinical characteristics and biochemical parameters were detected and compared. The patients with sight-threatening diabetic retinopathy had significantly lower serum 25-hydroxyvitaminD concentrations and higher prevalence of vitaminD deficiency than other two groups (all P<0.05). In addition, there was a downward trend in average 25-hydroxyvitaminD level with the increased stages of diabetic retinopathy (P<0.01). The prevalence of diabetic retinopathy and sight-threatening diabetic retinopathy in patients with vitaminD deficiency was also higher than in those without vitaminD deficiency (both P<0.01). After adjusting for all potential confounders, vitaminD deficiency was still associated with increased risk of diabetic retinopathy (odds ratio 1.93) and sight-threatening diabetic retinopathy (odds ratio 2.42) (both P<0.01). Logistical regression analysis further revealed that vitaminD deficiency was an independent risk factor for diabetic retinopathy (β=0.66) and sight-threatening diabetic retinopathy (β=0.93) (both P<0.01). ROC analysis indicated that a serum 25-hydroxyvitaminD level <15.57ng/ml suggested the occurrence of sight-threatening diabetic retinopathy (odds ratio 2.38, P<0.01). VitaminD deficiency is an independent risk factor for diabetic retinopathy and sight-threatening diabetic retinopathy. The prevalence of sight-threatening diabetic retinopathy doubles when the serum 25-hydroxyvitaminD level is <15.57ng/ml.