Active clinical trials for "Vitamin D Deficiency"

The purpose of this study is to investigate the presence of central sensitization in vitamin D deficiency and its effect on cutaneous silent period, pain, and quality of life. The secondary purpose of the study is to investigate whether a change in cutaneous silent period parameters, pain severity and neuropathic sensitization and quality of life after vitamin D replacement.

This is a pilot randomized, controlled trial of Vitamin D supplementation in patients on peritoneal dialysis to determine the feasibility of a future full-scale RCT exploring if oral administration of vitamin D3 could reduce the risk of subsequent Peritoneal dialysis-related (PD-related) peritonitis. Aims of the study: Aim 1: To determine the feasibility of oral vitamin D supplementation among PD patients who have recovered from a recent episode of peritonitis. Aim 2: To examine the effect of vitamin D supplementation on the risk for peritonitis among patients on peritoneal dialysis.

There is a consensus that vitamin D deficiency is a public health issue because of its implications in several diseases including, osteopenia, osteomalacia, heart disease, diabetes (type I and II), inflammatory diseases, multiple sclerosis and rheumatoid arthritis. Studies in sunny countries have shown that vitamin D deficiency is a common phenomenon, despite the abundance of sunlight in these places, which shows the influence of diet, skin pigmentation, cultural habits and also genetic factors on the metabolism of this vitamin. Thus, the study hypothesis is that vitamin D supplementation is required to obtain the optimal serum concentration in Brazilian people living both in Brazil and in the United Kingdom and that this response is dependent on the initial levels, being influenced by sunlight exposure, skin pigmentation, diet and polymorphisms of the vitamin D receptor gene. Two controlled, randomized, double-blind clinical trials were held (one in the UK and the other in Brazil) over a period of 12 weeks, with female subjects, Brazilian, aged 20 to 59 years. The women selected were divided into two groups: Placebo Group and Supplemented Group, the latter received vitamin D 600 IU. After the analysis of the effect of vitamin D supplementation compared to placebo, the investigators propose to analyse genome-wide transcriptomic expression in order to associate specific signal transduction and metabolic pathways to respective vitamin D responses. and a genetic risk score based on polymorphisms will be constructed. The 'systems level' approach will enable us to identify differences in gene expression and whether this explains why some individuals are 'good' responders or 'poor' responders to vitamin D supplementation. This is the first study that will examine two population groups of the same ethnic group and sex, living in different countries, with identical design studies. Our results first will determine how important supplementation and exposure to sunlight are for the serum level of vitamin D by comparing directly, using the same methodology, people living in different latitudes, as well as the genetic influence on the response to supplementation. The data will also provide both countries key data about the need to reconsider new revisions to dietary recommendations for vitamin D in adults.

Objectives: The investigators conducted a prospective study in Belgium with the objective to determine the proportion of subjects identified at moderate-to-high risk for AMD, based on the STARS® questionnaire, in need of nutritional supplementation by assessing their vitamin D, zinc oxide and fatty acid profile status. Methods: This multicentre epidemiological intervention pilot study involved 50 Belgian subjects with no AMD or early AMD, aged over 55, at moderate-to-high risk for AMD based on a simplified AMD risk assessment scale (STARS®) score ≥ 10, not taking vitamin D or trace nutrient containing supplements. Outcome data was collected during a one-time subject interview comprising of clinical eye examinations (typically visual acuity), the STARS® questionnaire, visual acuity assessment, an OCT scan on the macula, and fundus photography. Blood samples were collected from the patients and serum analysis was performed to determine the levels of omega-6 to omega-3 ratio, EPA and DHA, zinc and cupric oxide, and vitamin D, recognised as key nutrients involved in AMD pathophysiology.

Retinal tissue parameters of pediatric patients with vitamin D deficiency will be evaluated in this prospective case-control study. The patients will be divided into 2 groups according to the vitamin D level. Retinal vessel diameters, retinal nerve fiber evaluation, choroidal thickness will be evaluated. Choroidal thinning decrease in retinal artery diameter and increase in retinal vein diameter will be detected in the vitamin D deficiency group.

Asthma is a disease characterised by chronic inflammation of the airways leading to symptoms including periods of shortness of breath, wheezing and a tight chest due to airway narrowing in affected patients. Current data show that one in 12 adults are currently receiving treatment for asthma in the United Kingdom (UK), with the UK having some of the highest rates in Europe. In the winter, 30-40% of the UK population are vitamin D deficient with some asthma patients having significantly lower vitamin D levels compared to normal patients. Vitamin D has been shown to be involved in the development of immune-related disorders including asthma. Cross-sectional research has shown that reduced vitamin D levels are associated with reduced lung function, increased airway hyper-responsiveness and reduced response to glucocorticoids, suggesting vitamin D levels may also implicate asthma treatment. To date, there have been three randomised controlled trials (RCT) assessing the effect of vitamin D supplementation in adults with symptomatic asthma. These trials have not found a significant effect of vitamin D supplementation on asthma. However, these studies relied on high doses of vitamin D with long time periods between doses. There is a requirement for RCTs in adults with daily supplementation of lower doses of vitamin D as it has been suggested that daily supplementation is more effective for inducing non-classical actions of vitamin D. However, vitamin D has been found to significantly improve airway function as measured by forced expiratory volume in one second (FEV1) in adults supplemented with 100, 000 international units (IU) vitamin D intramuscularly plus 50, 000 IU oral vitamin D weekly. Therefore, the effect of daily dosing on lung function also requires investigation. Furthermore, these trials have focussed on clinical outcomes without investigating the cellular mechanisms affording protection.

This is a randomized, placebo-controlled trial of vitamin D supplementation with 20mcg cholecalciferol (to achieve a total intake of 25mcg/day), with or without 500mg calcium to assess vitamin D requirements in lactating women and to ascertain whether vitamin D supplementation at levels sufficient to achieve defined thresholds of maternal serum 25-hydroxyvitamin D will increase the vitamin D content of maternal milk. The study will also report serum 25-hydroxyvitamin D in maternal-cord dyads over a 12-month period and describe the relationship between them. Information on maternal iPTH levels, anthropometry, diet and sun exposure will also be reported.

Study will look at baseline Vitamin D levels, calcium, albumin, liver enzymes, testosterone, osteocalcin, urine N telopeptides, bone mineral density, nutritional assessment and physical activity assessment of boys with hemophilia A or B (ages 2-20 yrs). Patients with low vitamin D levels will receive therapeutic doses of Vitamin D. At end of one year follow up studies will be repeated.

The human immune system produces a protein called hCAP18 (also known as LL-37 or cathelicidin). This protein is believed to help the body to fight infections. Studies suggest that vitamin D may important in the production of hCAP18. This study is designed to test the ability of two different forms of vitamin D to affect levels of hCAP18. Vitamin D and hCAP18 levels will be measured during an initial visit. Individuals who are vitamin D deficient will be randomly assigned to receive one of two forms of vitamin D for two weeks. After this, follow-up levels will be measured.

Other studies suggest that low Vitamin D levels may contribute to musculoskeletal pain. Hypothesis: Administration of oral Vitamin D supplements will improve vague musculoskeletal pain in children.