Calcium and vitamin D supplement intake may increase arterial stiffness in systemic lupus erythematosus patients

Low serum levels of 25-hydroxyvitamin D (25(OH)D) have been associated with a higher frequency of risk factors and cardiovascular disease. The aim of this study is to evaluate the association of 25(OH)D, cardiovascular risk factors, and subclinical atherosclerosis in systemic lupus erythematosus (SLE) patients.

Forty-seven female SLE patients were studied. Data collected included demographics, SLE activity, disease damage, cardiovascular risk factors, and markers of subclinical atherosclerosis. Patient treatments and vitamin D and calcium supplementation (VitD-Ca) were recorded. Vitamin D deficiency was defined as serum 25(OH)D < 50 nmol/l measured by ultra-high-performance liquid chromatography. Atherosclerosis was assessed by measuring the carotid-femoral pulse wave velocity (PWV) by Doppler velocimetry and intima-media thickness (IMT) by B-mode ultrasound scanning.

61.7% of patients were vitamin D deficient with a mean level of 31.91 ± 10.21 nmol/l. Serum vitamin D concentration was significantly higher in the 23 patients taking VitD-Ca supplements than that in patients not supplemented (p = 0.004). No significant association was found between 25(OH)D serum levels and cardiovascular risk factors, disease activity, or different treatments for SLE. A significant positive correlation was found between 25(OH)D levels, PWV (p = 0.02), and IMT (p = 0.01); moreover, patients taking VitD-Ca supplements presented an increased arterial stiffness.

Patients with arterial stiffness showed higher levels of serum vitamin D and most of them were on VitD-Ca supplements. Although prospective studies with a larger number of patients and follow-up are needed, our findings suggest that VitD-Ca supplementation may have effects on SLE patients' arterial stiffness.