Effect of Vitamin D Deficiency and Replacement on Endothelial Function in Asymptomatic Subjects

• Published in: The journal of clinical endocrinology and metabolism Vol. 94; no. 10; pp. 4023 - 4030
• Main Authors: Tarcin, Ozlem, Yavuz, Dilek Gogas, Ozben, Beste, Telli, Ahu, Ogunc, Ayliz Velioglu, Yuksel, Meral, Toprak, Ahmet, Yazici, Dilek, Sancak, Seda, Deyneli, Oguzhan, Akalin, Sema
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Oxford University Press 01.10.2009; Endocrine Society
• Subjects: 25-Hydroxyvitamin D; Adult; Arteriosclerosis; Asymptomatic; Atherosclerosis; Atherosclerosis - etiology; Atherosclerosis - physiopathology; Biological and medical sciences; Biomarkers - blood; Blood Flow Velocity; Blood Pressure; Brachial Artery - physiopathology; Cardiovascular diseases; Endocrinopathies; Endothelium, Vascular - drug effects; Endothelium, Vascular - physiopathology; Feeding. Feeding behavior; Female; Foot & mouth disease; Fundamental and applied biological sciences. Psychology; Glucose tolerance; Humans; Insulin; Insulin Resistance; Leptin; Leptin - blood; Linear Models; Lipid peroxidation; Lipid Peroxidation - drug effects; Male; Medical sciences; Oxidative stress; Oxidative Stress - drug effects; Receptor mechanisms; Risk Factors; Sensitivity analysis; Thiobarbituric acid; Treatment Outcome; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vertebrates: endocrinology; Vitamin D; Vitamin D - administration & dosage; Vitamin D - analogs & derivatives; Vitamin D - blood; Vitamin D - therapeutic use; Vitamin D Deficiency - blood; Vitamin D Deficiency - complications; Vitamin D Deficiency - physiopathology; Vitamin D receptors; Vitamin deficiency; Waist-Hip Ratio; Human; Obesity; Endothelial cell; Nutrition; Nutrition disorder; Metabolic diseases; Asymptomatic; Replacement; Endocrinology; Nutritional status; Endothelium
• ISSN: 0021-972X; 1945-7197; 1945-7197
• DOI: 10.1210/jc.2008-1212

Context: Vitamin D receptors are present in many tissues. Hypovitaminosis D is considered to be a risk factor for atherosclerosis. Objective: This study explores the effects of vitamin D replacement on insulin sensitivity, endothelial function, inflammation, oxidative stress, and leptin in vitamin D-deficient subjects. Design, Setting, and Patients: Twenty-three asymptomatic vitamin D-deficient subjects with 25-hydroxyvitamin D [25(OH)D] levels below 25 nmol/liter were compared with a control group that had a mean 25(OH)D level of 75 nmol/liter. The vitamin D-deficient group received 300,000 IU im monthly for 3 months. The following parameters were evaluated before and after treatment: vitamin D metabolites, leptin, endothelial function by brachial artery flow mediated dilatation (FMD), insulin sensitivity index based on oral glucose tolerance test, and lipid peroxidation as measures of thiobarbituric acid reactive substances (TBARS). Results: FMD measurements were significantly lower in 25(OH)D-deficient subjects than controls (P = 0.001) and improved after replacement therapy (P = 0.002). Posttreatment values of TBARS were significantly lower than pretreatment levels (P < 0.001). A positive correlation between FMD and 25(OH)D (r = 0.45; P = 0.001) and a negative correlation between FMD and TBARS (r = −0.28; P < 0.05) were observed. There was a significant increase in leptin levels after therapy, and the leptin levels were positively correlated with 25(OH)D levels (r = 0.45; P < 0.05). Conclusions: This study shows that 25(OH)D deficiency is associated with endothelial dysfunction and increased lipid peroxidation. Replacement of vitamin D has favorable effects on endothelial function. Vitamin D deficiency can be seen as an independent risk factor of atherosclerosis. Hypovitaminosis D-associated endothelial dysfunction may predispose to higher rates of cardiovascular disease in the winter.Endothelial dysfunction by flow mediated dilatation (FMD) in asymptomatic vitamin D deficient subjects improves significantly after vitamin D replacement.