Jiaojiao T, Haihong L, Yuping M, et al. - Researchers intended to determine if there is an association between vitamin D supplementation and the characteristics of type 2 diabetes mellitus complicated with lower extremity arterial disease. Clinical data were obtained from 514 patients and 148 healthy individuals treated at the First Hospital of Lanzhou University from January 2012 to June 2019, including the clinical data, ankle-brachial index, and lower limb artery angiography medical records. In patients with type 2 diabetes mellitus complicated with lower extremity arterial disease, the serum level of 25(OH)D is decreased, and the level of 25(OH)D is associated with stenosis and occlusion risk, particularly in the inferior genicular artery in T2DM complicated with LEAD. A high level of 25(OH)D in type 2 diabetes with a lower extremity arterial disease can be a protective factor.