View clinical trials related to Vitamin D Deficiency.
Filter by:Hypothesis: Vitamin D supplementation lower renin-angiotensin system activity in obesity. Specific Aim: To investigate whether Vitamin D supplementation in obesity improves the vascular sensitivity to angiotensin II.
The purpose of this study is to determine if infrequent administration of oral vitamin D megadoses is effective treatment to maintain serum 25-hydroxyvitamin D(3) above target levels of 50-75 nmol/L. The investigators hypothesize that 100 000 IU or at least 200 000 IU vitamin D3 in every three months would be effective and safe treatment to achieve the target levels.
The study is designed to evaluate the increment of serum 25 (OH) vitamin D levels in normal weight adolescents following a 12-week supplementation with Vitamin D3 2000 IU/day.
The purpose of this study is to determine if the vitamin D binding protein genotype influences circulating vitamin D levels and if it may have functional consequences on vitamin D activity.
In the United States, cardiovascular disease causes over one-third of all deaths and vitamin D deficiency is an epidemic. An increasing body of data suggests that low vitamin D status adversely impacts the cardiovascular system. It is our fundamental hypothesis that vitamin D deficiency is a risk factor for cardiovascular disease by causing endothelial dysfunction. Moreover, we hypothesize that vitamin D supplementation will restore endothelial function, thereby reducing cardiovascular disease risk. This pilot research will be conducted in 64 post-menopausal women participating in an existing study of vitamin D supplementation (32 will receive vitamin D3 2,500 IU daily, the others matching placebo) and will explore the effects of vitamin D on endothelial function and arterial reactivity. Post-menopausal women aged 55-65 years are chosen due to their highest risk for development of a subsequent new cardiovascular disease diagnosis. All study participants will have fasting laboratory and noninvasive vascular ultrasound studies performed at baseline and four months later. The primary outcome measure of this pilot study is change in markers of endothelial function and arterial stiffness with vitamin D3 therapy. If our hypotheses are correct, our long-term goals include investigation of the effect of vitamin D repletion on subclinical atherosclerosis and subsequent cardiovascular events.
IBD is caused by an abnormal immune response to the gut bacteria in people who are genetically predisposed. There has been a huge increase in the number of people diagnosed with IBD since World War II, likely due to changes in our environment. It is possible that the abundance of vitamin D in the body may be one of those environmental factors that the investigators can control to make patients with IBD better. Vitamin D acts on cells of the immune system and causes many effects, including the production of a "natural antibiotic" called cathelicidin. The investigators know that when people are supplemented with vitamin D, levels of cathelicidin produced by these immune cells increase. By supplementing children with Crohn's disease with vitamin D, the investigators may be able to alter their immune system "naturally," making their disease better. A consensus of vitamin D experts believes that vitamin D levels need to reach a level of 40-70 ng/mL in the blood in order to have effects on the immune system. Raising vitamin D levels to this range is one of the goals in the current study.
Hypocalcemia is one of the most frequent complications of total thyroidectomy, a procedure used for benign as well as malignant conditions of the thyroid gland. Postoperative hypocalcemia is usually caused by hypoparathyroidism. Vitamin D is implicated in calcium metabolism as it increases intestinal calcium transport and regulates parathormone production. Aim of the present study is to evaluate preoperative vitamin D levels as a prognostic factor for postoperative hypocalcemia and hypoparathyroidism.
The purpose of this study is to determine whether a daily supplement of vitamin D, taking before and during pregnancy, effects child birth weight, pre- and postpartum complication and bone mineral density during lactation.
Obesity is an increasing health problem with numerous metabolic complications. Vitamin D deficiency is common in obesity, and in epidemiological studies vitamin D deficiency has been linked to metabolic complications, such as type 2 diabetes, insulin resistance and cardiovascular disease, as well as myopathy, osteoporosis and depression. In obesity, a low grade inflammation is present in the fat tissue, thereby releasing inflammatory molecules to the blood stream. In cell line studies as well as small clinical studies vitamin D has been shown to have the ability to reduce inflammation and cell growth. In the present study the investigators wish to investigate the effect of vitamin D on fat-, muscle and bone metabolism. 30 healthy obese subjects will be treated with cholecalciferol 175 micrograms daily for 6 months and will be compared with 30 healthy obese subjects treated with placebo. The investigators hypothesize that restoring vitamin D levels in vitamin D deficient obese subject will reduce inflammation and thereby reduce obesity-related complications. The effect will be evaluated as follows: - Levels of circulating inflammatory markers will be examined in blood samples collected prior to and after treatment. - Effects on fat- and muscle metabolism will be evaluated in fat- and muscle samples taken before and after treatment. - Effects on fat distribution will be evaluated by MRI scan before and after treatment. - Effects on insulin sensitivity will be evaluated by hyperinsulinaemic euglycaemic clamp performed on a subgroup of subjects with impaired fasting glucose. - Effects on bone marrow density will be evaluated by DEXA scans before and after treatment. - Effects on quality of life and depression score will be evaluated by questionnaires used before and after treatment.
Our objective is to demonstrate that providing supplemental vitamin D to children with new onset DM will significantly decrease the levels of HbA1c and insulin requirement by the following methods. 1. Identify how often vitamin D levels are low in patients with new onset Type 1 diabetes mellitus (DM). 2. Record the hemoglobin A1c (HbA1c) level (which reflects the average blood sugar level over the past few months) and document insulin requirements before and after vitamin supplementation is given. Hypothesis: Maintaining vitamin D levels >30 ng/ml will decrease HbA1c and insulin requirements.