View clinical trials related to Vitamin D Deficiency.
Filter by:There is a high prevalence of vitamin D deficiency in Switzerland. In indoor-athletes as well as wheelchair users, vitamin D deficiency occurs even more often. It is well established that vitamin D deficiency has a negative effect on health. However, vitamin D supplementation in individuals with a vitamin D deficiency has a positive effect on muscle performance. In recently published studies with able-bodied subjects, it has been shown that a normal vitamin D level (>75nmol/L) can only be achieved with a high-dose supplementation of vitamin D. The aim of this study is to examine the effect of vitamin D supplementation on exercise performance in wheelchair athletes with vitamin D deficiency . All participants with a vitamin D deficiency are assigned to the intervention group and treated with 6000 IU of vitamin D3 daily over a period of 12 weeks. All participants who have a normal vitamin D level will receive placebo treatment (control group). The physical performance is measured three times at baseline, after six weeks and 12 weeks. The measurements include a Wingate and a dynamometer test.
Children with Cystic Fibrosis, ages greater than and equal to 36 months of age and less than or equal to 18 years of age, with a 25OHD level less than 30 ng/dL will be asked to participate in this study. Upon consent, they will be given oral cholecalciferol supplementation of 250,000 IU during their next CF clinic visit. The safety will be assessed by measuring a serum calcium level within 1 week of supplementation. Efficacy will be assessed using repeated 25OHD levels throughout the course of 12 months. Feasibility will be assessed with the previous two measures as well as a brief questionnaire administered via telephone within 1 week of supplementation.
Determine differences in serum vitamin D metabolism by genetic ancestry.
The objective of this study is to assess the effects of a high-dose vitamin D3 on the composition of gut and lung microbiota in adolescents and adults with cystic fibrosis who are vitamin D deficient.
To investigate possible physiologic interactions between the adrenal- and the parathyroid glands in patients with secondary hyperparathyroidism.
Total 25(OH)D is currently used as a biomarker of vitamin D status. However, there is some debate as to whether total 25(OH)D is the best marker to use. It has been suggested that free vitamin D may be better because it may be more biologically available. There are also some uncertainties about how we treat vitamin D deficiency. A single dose is attractive because it is certain that the patient has had the dose and there is no requirement for ongoing compliance, but it is still not clear what the best dose is to give. Also, recent studies have highlighted that high dose vitamin D supplementation may increase the risk of falling in older populations. The investigators believe that studying how free vitamin D responds to different bolus doses is the best way address some of the current research gaps, including what is the best biomarker of vitamin D status, what is the mechanism of vitamin D toxicity and what is a safe bolus dose to treat deficiency. The investigators will study changes in total and free 25(OH)D, and also clinical response, to three different bolus doses of vitamin D (50 000IU, 150 000IU and 500 000IU) in 84 vitamin D deficient postmenopausal women, over a three month period with 5 study visits. A concurrent control group of 28 vitamin D sufficient postmenopausal women will also be recruited. This will allow the investigators to determine how total and free vitamin D change with bolus dosing and whether there is a disproportionate rise in free 25(OH)D with higher doses that may lead to hypercalcemia and falls.
The primary aim of the current study was to investigate whether the consumption of vitamin D3 enriched, reduced-fat yellow cheese can counterbalance the expected decrease in serum 25-hydroxyvitamin D concentration during winter in postmenopausal women in Greece, and in what degree it can contribute as a potential food-based strategy for the prevention of vitamin D deficiency. A secondary aim was also to investigate any potential effect of the intervention in several quality of life (QoL) indices in the population of postmenopausal women under study.
This study investigated whether vitamin D receptor gene polymorphism is altered in primary open-angle glaucoma subjects carrying the risk allele and vitamin D deficiency is an important factor in the development of glaucoma. Primary open-angle glaucoma patients and age-matched people in the Han population were enrolled. Serum levels of 1a, 25-Dihydroxyvitamin D3 were measured by enzyme-linked immunoabsorbent assay. Vitamin D receptor polymorphic analysis was studied by real-time polymerase-chain reaction high resolution melting analysis.
The purpose of this study is to determine if there is correlation between Vitamin D deficiency and spinal disease/spinal fusion surgery.
The purpose of this study is to evaluate the effect of daily consumption of one or two CALIN+ pot(s) versus no intake of product, after 4, 8, 12 and 16 weeks, on the evolution of the serum concentration of 25-hydroxy vitamin D (25OHD) (D2 + D3) in postmenopausal women.