This study, conducted by Chinese researchers, investigated the relationship between vitamin D deficiency and diabetic retinopathy in patients with type 2 diabetes. In total, 1520 patients with type 2 diabetes were recruited and divided into three groups: no diabetic retinopathy and two groups based on their stage of the disease. Patients with the most advanced stage of the disease had significantly lower vitamin D concentrations compared with the other two groups. Also, a downward trend in vitamin D levels was observed in patients with increased stages of diabetic retinopathy. More advanced diabetic retinopathy was more frequent in patients with vitamin D deficiency than in those with normal vitamin D levels. In conclusion, vitamin D deficiency is an important risk factor for diabetic retinopathy. More details can be found in the study.
He et al.