Active clinical trials for "Vitamin D Deficiency"

To investigate the role of Vitamin D (VD) deficiency as a risk factor for the development and malignant transformation of Oral lichen planus (OLP) taking into consideration sex, dietary habits, sun exposure, socioeconomic status and psychological factors.

Many studies have pointed out that patients with vitamin D deficiency have a longer stay in the intensive care unit and a poor prognosis. Previous multi- center prospective observational study in Taiwan reveals that the prevalence of vitamin D deficiency in critically ill patients in northern Taiwan is 59%, and the prevalence of severe vitamin D deficiency is 18%. Several prediction models of vitamin D deficiency had been built for the general population but not patients admitted in intensive care units. This multi-center retrospective study aims to develop and validate a score-based prediction model for severe vitamin D deficiency in critically ill patients. Investigators will review the data of previous multicenter, prospective, observational study. For temporal validation, the data will be divided into a derivation cohort (first 80% of the data set based on chronology) and a validation cohort (the remaining data set). The development and validation of the models will be carried out following the recommendations established in the Transparency Reporting of a multivariable prediction model for Individual Prognosis or Diagnosis (TRIPOD) initiative.

The purpose of this study is to determine the prevalence of vitamin D deficiency among the population of pregnant women receiving prenatal care and giving birth at the investigators' clinic. The further purposes are to identify the population at risk for vitamin D deficiency and to analyse whether vitamin D deficiency is associated with pregnancy complications.

In 2012, a cross-sectional survey sampling 1,966 community-dwelling old people was conducted. Structurized questionnaires were interviewed face-to-face by well-trained staffs. An overnight fasting blood were obtained for biochemistry parameters.

Vitamin D deficiency may be under-diagnosed in sickle cell disease French children. Therefore, the investigator need an epidemiologic study about the prevalence of vitamin D deficiency in this specific population. There are not specific guidelines neither testing nor treatment. The investigator propose to test vitamin D status in all children with sickle cell disease who are consulting their referring haematologist doctor or in the emergency ward.

Vitamin D deficiency is a modifiable risk factor for poor bone health. Familial correlation of serum 25-hydroxyvitamin D concentration (25(OH)D) was reported in twin- or family-based studies, mostly from Caucasian parent-offspring pairs. However, data on the familial association of 25(OH)D in extended family structure and the relative contribution of genetic and shared environmental factors on serum 25(OH)D level are limited in Asian populations. In this study, the investigators aimed to assess the relative contribution of additive genetic and environmental components on serum 25(OH)D level by variance components method in a nationwide family-based cohort. Further, the investigators will evaluate the association of vitamin D status of index individual with prevalent vitamin D deficiency of each family member including spouse, offspring, sibling, and grand-offspring. Additive influences of paternal and maternal vitamin D status on offspring will be also investigated.

The goal of this prospective cohort study is to learn about the overall and seasonal prevalence of vitamin D insufficiency and its determinants in a population of women with infertility who will go through in vitro fertilization in Sweden. The main questions it aims to answer are: What is the prevalence of vitamin D insufficiency? What are the determinants of this insufficiency? Participants will be asked to complete a questionnaire validated for dietary assessment of vitamin D intake and sun exposure habits and they will leave a blood sample for measurement of 25(OH)D concentration. Researchers will compare the in vitro fertilization outcomes between women with vitamin D insufficiency and sufficiency to see if there is any difference.

Background: Vitamin D3 (VD) is an oil soluble vitamin formed in the skin during exposure to UV light. It is essential for bone and calcium metabolism, insulin reactivity, immune system etc. The dietary sources of VD are scarce, and insufficient. Epidemiological studies link proper VD status with lower risks of bone fracture, hypertension, diabetes, cancer and more. VD deficiency is widespread, mainly due to avoidance of sun exposure due to fear of melanoma. Therefore there is an urgent need to enrich staple foods & beverages with VD, to prevent deficiency. A novel technology was developed , for nanoencapsulating VD within casein micelles (CM) (natural milk protein nanoparticles). Previously we have found that the bioavailability of VD in CM in 1% fat milk was similar to that in an aqueous dietary supplement based on a synthetic emulsifier- Tween 80- which is sometimes used by the industry to add VD into milk. The main research question studied in the current project is: how will the bioavailability of VD be affected by its delivery in CM compared to its delivery using Tween 80 in a fat free milk product, like nonfat yogurt. Hypothesis: The open molecular structure of caseins, which evolved to be easily digestible, may facilitate the bioavailability of VD nanoencapsulated in CM, so that it will not be less than that in Tween 80, which is considered to be good. CM are particularly useful for oil-soluble micronutrient delivery in non-fat products. The most widely consumed nonfat milk product is 0% fat yoghurt, chosen it for this study. Methods: Yoghurts will be made from 3 milk formulations: Skim milk (0% fat) enriched with 50,000 international units (IU) VD in 150 gr product, in CM. Skim milk with same dosage of VD, emulsified with Tween 80. Placebo: skim milk without added VD. 90 healthy adults, aged 18-65, having passed a medical qualification examination, will be randomly assigned to 3 groups. Following over-night fasting they will each consume a 150 gr yoghurt sample as detailed above, and be requested to fast 2 more hours. Blood will be sampled before yoghurt consumption, and after 1, 7 and 14 days following consumption. Blood-serum level of 25(OH)D (the form of VD used as a status indicator in routine blood tests), by chemiluminescence immunoassay (CMIA). Expected findings: The bioavailability of VD in CM will not be lower than that in Tween 80, in 0% fat yoghurt. Significance of the study: With the widespread VD deficiency, decreased fat consumption and rising demand for using only natural ingredients there is great importance in delivery of VD and other fat-soluble micronutrients in protein-based delivery systems, like CM, instead of using synthetic emulsifiers, and it is imperative to assure the bioavailability is not compromised by this dramatic change. CM solubilize VD and help uniformly distribute it in aqueous products and protect it against heat, oxidation and UV.

Hypothesis : Vitamin D serum concentration is decreased in the first trimester in pregnant women who will develop preeclampsia in the second or third trimester compare to a control group Primary purpose : To determine the vitamin D status in the first trimester in a large population of french pregnant women in order to evaluate the importance of the vitamin D deficiency in France and correlate this deficiency with preeclampsia

The purpose of this study is to evaluate level of vitamin D in pediatric asthma and relationship between vitamin D and level control of asthma.