Vitamin D deficiency is associated with risk of developing peripheral arterial disease in type 2 diabetic patients

Abstract

Background: The relationship between vitamin D levels and peripheral arterial disease (PAD) remains unclear. We assessed the association of serum 25-hydroxyvitamin D (25(OH)D) levels with the prevalence of PAD in patients with type 2 diabetes mellitus(T2DM).

Methods: A total of 1018 T2DM patients participated in this cross-sectional study. Serum 25(OH)D levels were measured and risk factors of PAD were recorded. PAD was diagnosed as an ankle-brachial index (ABI) < 0.9.

Results: The mean age of the diabetic patients was 58.59 ± 11.34 years. Of all the patients, only 20.1% had a 25(OH)D level ≥ 20 ng/mL. Compared to patients without PAD, serum 25(OH)D levels were significantly lower in those with PAD (14.81 ± 8.43 vs. 11.55 ± 5.65 ng/mL, P < 0.001). The overall prevalence of PAD was 7.7%. From the highest level (≥ 20 ng/mL) to the lowest level (< 10 ng/mL) of serum 25(OH)D, the prevalence of PAD was 2.8, 7.5 and 10.7% respectively. After adjustment for age, sex, body mass index (BMI), smoking status and season, compared to patients with serum 25(OH)D levels ≥20 ng/mL, the odds ratios of PAD in patients with a level of 10 to < 20 ng/mL and < 10 ng/mL was 3.587(95% CI: 1.314-9.790) and 5.540(95% CI: 2.004-15.320), respectively. When further considering the influence of coronary heart disease (CHD), hypertension and cerebral infarction, the ratios changed to 3.824(95% CI: 1.378-10.615) and 5.729(95% CI: 2.028-16.187), respectively. And after further adjustment for the duration of diabetes, glycated hemoglobin (HbA1c) and glomerular filtration rate (GFR), the ratios changed to 3.489(95% CI: 1.100-11.062) and 3.872(95% CI: 1.168-12.841), respectively.

Conclusions: Reduced serum vitamin D levels were associated with an increased risk of PAD in T2DM patients. Randomized interventive clinical studies are required to verify the effects of vitamin D supplementation on PAD.

Keywords: 25-hydroxyvitamin D; Peripheral arterial disease; Type 2 diabetes; Vitamin D deficiency.

Fig. 1

Flowchart of the study. NPAD: no peripheral arterial disease; PAD: peripheral arterial disease

Fig. 2

Comparison of the three logistic regression models for diagnosing PAD in patients with T2DM

Fig. 3

A simple-to-use nomogram for diagnosing PAD. Instructions for using the nomogram: Draw a perpendicular line from the axis of each risk factor to determine the corresponding “POINTS” . The total points of all risk factors are then obtained. After that, draw a line descending from the axis “TOTAL POINTS” until it reaches the axis of “Rik of PAD”. For binary variables (except “Duration”), 0 = no and 1 = yes. For duration categories, 0 = duration of diabetes≥10 years and 1 = duration of diabetes<10 years. For season categories, 0 = spring, 1 = summer, 2 = autumn, 3 = winter. For smoke categories, 0 = never, 1 = former and 2 = current. For VDD categories, 0 = serum 25(OH)D ≥ 20 ng/ml, 1 = serum 25(OH)D 10 to<20 ng/ml and 2 = serum 25(OH)D<10 ng/ml