Association between vitamin D status and diabetic foot in patients with type 2 diabetes mellitus

To assess the association between vitamin D and diabetic foot (DF) in patients with type 2 diabetes mellitus (T2DM), in order to summarize clinical evidence in the prevention and treatment of DF.

Between January 2012 and December 2019, a total of 1,721 hospitalized patients with type 2 diabetes mellitus were continuously enrolled in West China Hospital, Sichuan University, and divided into DF and non-DF groups according to whether they had DF, and divided into four subgroups according to the admission season. The 25-OH-vitamin D levels were compared between groups and subgroups, and independent risk factors discussed for the occurrence of DF.

The vitamin D insufficiency and deficiency rate were higher in the DF group (77.51%) than in the non-DF group (59.2%). The 25-OH-vitamin D levels were lower in the DF group (35.80 nmol/L) than in the non-DF group (45.48 nmol/L) (P < 0.001). Patients with poor glycemic control had lower 25-OH-vitamin D levels (P = 0.01). The levels of 25-OH-vitamin D were lower in winter and spring. In the same season, the levels of 25-OH-vitamin D in patients with DF were still lower (P < 0.001). The 25-OH-vitamin D levels of patients with Wagner grades 0 to 5 showed a downward trend (P = 0.114). The 25-OH-vitamin D level was independently associated with diabetic foot (P < 0.001, OR = 0.986).

The low serum vitamin D level was significantly associated with a higher prevalence of DF among Chinese patients with type 2 diabetes mellitus. Although vitamin D levels vary seasonally, patients with DF were always at higher risk of having vitamin D insufficiency and deficiency.