Active clinical trials for "Vitamin D Deficiency"

This study will encompass an analysis of an eventual association between vitamin D status (maternal during pregnancy, at birth or at 5 years) and hand grip strength at 5 years in children from Odense Child Cohort. Odense Child Cohort is a large-scale, prospective, population-based, follow-up study. Mothers and their children born from January 2010 to December 2012 and resident in the Municipality of Odense, Denmark, are followed from early pregnancy up to adulthood. Data is obtained from questionnaires and medical records and venous blood samples were drawn and stored at a biological bank. Low muscle strength in children has been linked to adiposity, cardiovascular disease and metabolic risk factors and low muscle strength in adolescence has been shown to be a risk factor of early adulthood mortality. There are not many studies on muscle strength in small children. There is some evidence of vitamin D concentrations in the blood having a positive correlation to upper body muscle strength in adolescent girls. Hypovitaminosis D defined as serum 25-hydroxyvitamin D <50nmol/L was evident in 27,8% of the pregnant women and 47,7% of the new-born children in Odense Child Cohort. Animal studies have shown an effect of vitamin D on regulation of muscle function and development. Studies on humans adults have shown that vitamin D deficiency can lead to myopathy. Myopathy in children as a result of hypovitaminosis D is not well-studied. Given the high prevalence of hypovitaminosis D, mild or severe vitamin D-associated myopathy may be prevalent in preschool children. The objectives of this study are 1) to create reference values and determine predictors of hand grip strength at five years, 2) to analyze the associations between vitamin D at different time points and hand grip strength at 5 years.

Vitamin D deficiency is a risk factor for mortality but existing data are limited by missing standardization of laboratory methods for 25-hydroxyvitamin D (25[OH]D). In a European consortium of eight cohort studies we use protocols of the Vitamin D Standardization Program (VDSP) to obtain standardized 25(OH)D data. Individual participant data (IPD) meta-analyses using a one step procedure will be performed to study associations of original and standardized 25(OH)D with all-cause, cardiovascular, and cancer mortality.

This study evaluates the effect of Vitamin D3 supplementation in healing rate of tibia fractures in adult patients with low vitamin D. Half of participants will receive Vitamin D3 supplementation while the other will receive placebo.

The purpose of this study is to determine the association between serum 25-hydroxyvitamin D and HbA1c levels in diabetic patients with chronic kidney disease. The investigators hypothesized that serum 25-hydroxyvitamin D levels were negatively correlated with HbA1c levels.

Athletes and active individuals have been identified as an at-risk group for a low vitamin D status, specifically those residing in countries of higher latitude (such as the United Kingdom). This especially applies to those who train indoors for their sport, this is because Vitamin D is primarily produced following skin exposure to ultraviolet B (UVB) exposure. Vitamin D is essential for the maintenance of optimal bone and musculoskeletal health. It has also been suggested to play a role in the prevention of illness incidence, such as in upper respiratory tract infections (URTI). More recent research has indicated that an improved Vitamin D status may also play a role in enhancing exercise performance. Therefore, having a poor vitamin D status could negatively impact athletic training and competition. The purpose of this study is to evaluate the prevalence of vitamin D deficiency in university athletes and inactive controls in spring and autumn. During this study the subjects will be asked to visit the labs on two occasions, at the beginning of the study for baseline measurements, and again on two occasions at the end of the study. Participants will have the following outcomes assessed: Sport performance (vertical jump height, muscular strength and aerobic fitness), peripheral Quantitative Computed Tomography (pQCT) scan of the bone mineral composition of the tibia, total body composition via Dual Energy X-ray Absorptiometry (DEXA),total and hip/femoral head bone mineral density and content to assess fracture risk via DEXA. Serum 25(OH)D levels (≈15ml of whole blood will be collected for these measurements. Dietary intake using self-reported food diaries. In addition illness and injury incidence will be recorded daily throughout the study in a booklet provided to the participants.Throughout the trial, the participants will be contacted via telephone/ email on a monthly basis to discuss any issues and maintain good communication.

Schizophrenia and bipolar disorders are major public health problems. The second generation anti-psychotic drugs have efficacy for both positive and negative symptoms and a favorable risk profile as far as movement disorders. However, these drugs are associated with clinically significant weight gain and metabolic effects. The underlying mechanisms of these side effects are unclear, however in our preliminary studies with schizophrenic patients on atypical anti-psychotic drugs, we found that weight gain and vitamin D deficiency was present in about 50% of this population. Given the considerable heterogeneity among the patients on atypical anti-psychotics and potential for weight gain in vitamin D-deficient states, we propose that patients with schizophrenia who gain weight on atypical antipsychotic medications are vitamin D-deficient. This hypothesis will be tested in patients with schizophrenia receiving second-generation anti-psychotic drugs for a minimum duration of 4 months. Specific Aim: We predict that the patients with schizophrenia, who gain weight with antipsychotic treatment, are vitamin D-deficient compared to the patients who do not gain weight. We will examine circulating levels of serum 25(OH)D, mRNA transcripts and protein expression of vitamin D receptor (VDR) and the enzymes, CYP24A and CYP27B, in the white blood cells of the subjects and correlate with BMI and the blood levels of leptin and adiponectin.

This study will compare and assess the prevalence of osteopenia and vitamin D deficiency as well as effects of TDF on the patients' bone among HIV positive and negative patients.

Vitamin D receptors are expressed in activated different immune cells. It is not known, which immune cell type is targeted by exogenous vitamin D. Here, vitamin D-deficient individuals will receive once 100.000 I.U. vitamin D3 either intramuscular or subcutaneous in a double-blind placebo controlled setting. Immune cells will be monitored from the blood over time.

Poor vitamin D status is very common in African Americans. Periodontitis (gum disease) are shown to be related to theincreased risk of cardiometabolic diseases. Vitamin D is freely available and cheap supplement that has shown beneficialeffect in the immune system regulation and maintenance of the cardiovascular health. In this study The investigators hypothesize thatvitamin D supplementation for 16 weeks in African Americans with periodontitis will result in clinical improvement in theirgum health as well as their cardiometabolic risk profile

The role of vitamin D deficiency in female reproduction remains controversial. Early retrospective studies were inconsistent regarding the effect of serum 25-OH vitamin D levels on pregnancy rates in women undergoing in vitro fertilization (IVF), whereas two retrospective studies postulated that vitamin D deficiency may negatively affect pregnancy rates with an effect mediated through the endometrium. Taking into account that knock-out experiments have shown that vitamin D receptor null mice not only experience uterine hypoplasia but also impaired folliculogenesis, it might be hypothesized that vitamin D deficiency may have a detrimental effect on female ovarian reserve. This may be further supported by previous reports demonstrating that serum 25-OH Vitamin D levels correlates with antimullerian hormone (AMH) levels in women of advanced reproductive age. The aim of this study is to examine through a large set of prospectively recruited infertile women whether serum 25-OH-Vitamin D levels is related with the 2 most widely accepted biomarkers of ovarian reserve: serum AMH levels and antral follicle count (AFC).