Active clinical trials for "Vitamin D Deficiency"

Vitamin D deficiency is common worldwide, including in infants and children, and rickets remains a public health concern in many developing countries. The vitamin D status and prevalence of vitamin D deficiency in the Haitian population has not been studied. There is currently no approved point-of-care testing device for vitamin D deficiency. Iodine deficiency and resulting hypothyroidism is the leading cause of preventable neuro-developmental delay and cognitive impairment worldwide. Young infants and children are especially susceptible to sequelae of disruption in thyroid function given the dependence of the developing brain on sufficient levels of thyroid hormone. Perchlorate and thiocyanate have been described as potential environmental disrupters of thyroid function. Lead intoxication is a significant cause of disease throughout the world. Millions of people have suffered the effects of lead poisoning. Although most developed countries have taken drastic measures to limit the environmental lead levels, many countries in the developing world have not been able to address, or even assess, the problem. Our objectives are to study the following three components in 300 Haitian children between 9 months and 6 years of age in three different geographical areas of Haiti: 1) Vitamin D status and prevalence of rickets, environmental factors associated with low vitamin D levels, and the accuracy and efficacy of a vitamin D point-of-care testing (POCT) device for the screening of vitamin D insufficiency. 2) Iodine status and thyroid function, and environmental disruptors such as perchlorate and thiocyanate as potential risk factors for abnormal thyroid function. 3) Lead levels and the extent of childhood lead poisoning.

It is essential that serum 25(OH)D changes following surgery be clarified, and the mechanism(s) underpinning these changes be identified. As such, the overarching hypothesis of this study is that elective total hip arthroplasty reduces serum total 25(OH)D.

Hypothesis: 25-hydroxy vitamin D levels in non-itching hemodialysis (HD) patients will be higher than those in HD patients with itching 25-hydroxy vitamin D levels will be measured in non-itching hemodialysis patients and compared to levels previously measured in a previous study of 25-hydroxy vitamin D levels of patients complaining of itching.

The aim of this study is to investigate the bioavailability of vitamin D2 and D3 as measured by the increase of the specific hydroxy forms in serum (25(OH)D2 and 25(OH)D3, respectively, and by total 25(OH)D.

Hypocalcemia is a frequent adverse event after thyroidectomy. It is usually related to hypoparathyroidism, but preoperative hypocalcemia, hypomagnesemia or vitamin D deficiency contributes to it. This study aims to determine the frequency of vitamin D deficiency or insufficiency in patients submitted to thyroidectomy, to define the risk attributed to vitamin D deficiency to postoperative hypocalcemia, to identify other factors associated to postoperative calcium disorder, and to evaluate the benefit of preoperative treatment of vitamin D deficiency to prevent postoperative hypocalcemia.

The purpose of this study is to try to correlate vitamin D dosing and dosing adjustment with Vitamin D levels, measure affects of seizure medications on levels as well as pathologic fractures and bone density in severely cognitively impaired, non-mobile children and adolescents with CP.

Recent studies indicate that there is a relationship between cognitive decline and vitamin D deficiency. Up to now, no study has investigated the prevalence of vitamin d deficiency in patient with Alzheimer's disease. Our aim is to investigate the prevalence of vitamin D deficiency and analysis the associated characteristics in patients with Alzheimer's disease.

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.

Maternal vitamin D deficiency has been suggested to influence fetal and neonatal health. The role of placenta in vitamin D regulation is known but alteration of Vitamin D levels at placental pathologies is unknown. Placental calcification is usually thought to be a physiological aging process. Nevertheless, it can be a pathological change resulting from the effects of environmental factors on the placenta. The aim of the investigators study was to evaluate the relationship between placental calcification and maternal and cord blood 25-hydroxyvitamin-D3 [25(OH)D] and calcium concentrations in low-risk obstetric population at term and their consequences.

The purpose of this study is to investigate whether an association exists between serum vitamin D levels and IVF treatment outcome