Effect of a single, oral, high-dose vitamin D supplementation on endothelial function in patients with peripheral arterial disease: a randomised controlled pilot study
European Journal of Vascular and Endovascular Surgery, 08/02/2012

Stricker H et al. – In this pilot study, most patients with peripheral arterial disease (PAD) were vitamin D deficient. Vitamin D supplementation increased serum 25–hydroxyvitamin D without influencing endothelial function, arterial stiffness, coagulation and inflammation parameters, although the study was underpowered for definite conclusions.

• In this double–blind, placebo–controlled, interventional pilot study, authors screened 76 Caucasian patients with PAD for vitamin D deficiency.
• 62 were randomised to receive a single, oral supplementation of 100 000 IU vitamin D3 or placebo.
• At baseline and after 1 month, they measured serum vitamin D and parathormone levels, and surrogate parameters for cardiovascular disease.

• 65 of 76 patients (86%) had low 25–hydroxyvitamin D levels (<30 ng ml^–1); of those, 62 agreed to participate in the study.
• At baseline, only parathormone was related to vitamin D.
• In supplemented patients, vitamin D levels increased from 16.3 ± 6.7 to 24.3 ± 6.2 ng ml^–1 (P < 0.001), with wide variations between single patients; in the placebo group vitamin levels did not change.
• Seasonal factors accounted for a decrease of vitamin D levels by 8 ng ml^–1 between summer and winter.
• After 1 month, none of the measured parameters was influenced by vitamin substitution.