EFFECT OF VITAMIN D SUPPLEMENTATION ON ATHEROSCLEROTIC RISK MARKERS IN SUBJECTS WITH METABOLIC SYNDROME

Background and Aim: Metabolic syndrome is considered as a precursor of cardiovascular diseases. Since, in recent studies, vitamin D is advocated for cardio-protective roles, this study was designed to investigate the effects of vitamin D supplementation on Atherosclerotic risk markers in subjects with metabolic syndrome. Methods: This randomized double blind clinical trial was conducted in Tabriz, Iran. Eligible subjects (n=80) with metabolic syndrome were recruited thorough advertisement and were randomized to receive either vitamin D (50,000 IU/week) or matching placebo for 16 weeks. The consumption of 50,000 IU vitamin D per week was considered to be safe since the upper limit is 10,000 IU/d. Vascular inflammatory markers, Interlukin-6 (IL-6)and high sensitivity C - reactive protein (hsCRP);adhesion molecules, vascular cell adhesion molecule-1 (VCAM-1), E-selectin; and common carotid intima-media thickness (cCIMT) were measured at the beginning and end of the study. The study was registered at http://www.irct.ir (code: IRCT201409033140N14). Sixteen weeks supplementation with vitamin D increased median of serum 25-hydroxy vitamin D [25(OH)D] and mean calcium levels (p<0.001) in the intervention group. There was also a significant difference in parathyroid hormone (PTH) levels between two groups at the end of the study (p<0.001). Vitamin D treatment reduced IL-6 level after 16 weeks (p=0.027). Compared to baseline, E-selectin and VCAM-1 levels decreased significantly in vitamin D treated subjects; however, there were no significant differences between two groups. No effect of vitamin D supplementation was observed in either cCIMT or hsCRP concentration at the end of the study (P> 0.05). Conclusion: Vitamin D did decrease adhesion molecules and inflammatory marker in subjects with metabolic synrome. Thus, vitamin D might play a protective role in developing Atherosclerosis in high risk subjects.There needs large-scale long duration trials to support the beneficial effect of vitamin D on cardiovascular diseases.

Keywords:

vitamin D , Atherosclerotic risk , adhesion molecule , carotid intima-media thickness