Association between serum vitamin D level and cardiovascular disease in Chinese patients with type 2 diabetes mellitus: a cross-sectional study

The relationship between 25-hydroxyvitamin D (25(OH)D) status and cardiovascular disease (CVD) in the diabetes population still needs to be clarified. This study aimed to explore the association of 25(OH)D with CVD and cardiometabolic risk factors in Chinese population with type 2 diabetes mellitus (T2DM). This cross-sectional study was performed with 1378 hospitalized patients with T2DM. Participants were classified into three groups according to the serum 25(OH)D levels: vitamin D adequate, vitamin D insufficiency and vitamin D deficient. Multivariate logistic regression analysis, stratified analysis and interaction analysis were performed to determine the relationship between serum 25(OH)D levels and CVD outcome. After adjusting for confounders, serum 25(OH)D levels were significantly negatively associated with cardiovascular disease in type 2 diabetic patients [OR: 0.97 (0.94, 0.99), p = 0.0131]. Taking the vitamin D-sufficient group (≥ 20 ng/mL) as a reference, the vitamin D-deficiency group (< 12 ng/mL) was associated with a significantly higher risk of cardiovascular disease, with a 1.25-fold increased risk after adjusting for all potential confounders [OR: 2.25 (1.33, 3.79), p = 0.0023]. Stratification analysis showed that the association between vitamin D deficiency and increased risk of cardiovascular disease was particularly significant in women [OR: 4.32 (1.54, 12.12), p = 0.0055], older adults [OR: 4.14 (1.10, 15.56), p = 0.0355], normal-weight [OR: 4.09 (1.51, 11.10), p = 0.0056] and obese subjects [OR: 3.66 (1.03, 13.05), p = 0.0453]. Vitamin D deficiency was significantly associated with an increased risk of overweight/obesity [OR: 1.57 (1.10, 2.24), p = 0.0134], hypertension [OR: 1.81 (1.30, 2.51), p = 0.0004], hypertriglyceridemia [OR: 1.56 (1.12, 2.16), p = 0.0078] and reduced HDL-C [OR: 1.67 (1.19, 2.35), p = 0.0033]. Serum 25(OH)D levels were significantly negatively associated with CVD in T2DM patients and vitamin D deficiency was significantly associated with an increased risk of overweight/obesity, hypertension and dyslipidemia.