Active clinical trials for "Vitamin D Deficiency"

Assessing the combined effect of omega-3 fatty acid and vitamin D 3 on plasma osteocalcin levels

Objective: To examine the effect of vitamin D supplements on the pregnancy and clinical pregnancy rate in embryo transfer cycles. Design: Experimental study with a pre- and post-test. Setting: In Vitro Fertilization Center Patients: Its sample consisted of 118 women, 58 in the experimental group and 60 in the control group. Intervention(s): At the beginning of the infertility treatment, the experimental group took vitamin D supplements, and the control group did not. Vitamin D supplementation for infertile women includes regulation of a diet rich in vitamin D, educational and motivational interviews about insolation, and taking vitamin D orally. Main Outcome Measure(s): 25(OH)D and beta HCG levels

Vitamin D plays a significant role in calcium and phosphorus homeostasis for maintaining structural integrity and function of musculoskeletal system. Furthermore, recent studies have revealed that vitamin D can decrease the risk of many conditions other than skeletal disease, including autoimmune diseases, cancers, obesity and obesity-related diseases, such as type 2 diabetes and cardiovascular disease. Vitamin D may influence calcium absorption to affect obesity indirectly, regulate adipocyte differentiation and relieve the development of metabolic syndrome by mediating levels of inflammatory factors. Another indicator of bone metabolism-osteocalcin may also be involved in energy metabolism and glucose metabolism, and undercarboxylated osteocalcin (ucOC) is the form which has physiological activity. ucOC may recombine with the receptors on the surface of pancreas β cells, adipocytes, hepatocytes and intestinal endocrine cell to regulate insulin secretion and insulin sensitivity. Currently, the prevalence of vitamin D deficiency is a global problem in all age groups currently, even in countries with sun exposure all year around. The obesity group tend to have a higher incidence of vitamin D deficiency.Moreover, the obesity group tend to have a higher incidence of vitamin D deficiency and a lower level of serum osteocalcin. This study observed the changes of body composition and glucolipid metabolism and bone metabolism during weight loss, and investigated the correlations among them.

Several studies have demonstrated that D2 treatment is associated with a decrease in 25(OH)D3 level and therefore have proposed that D3 would be preferable in term of raising total 25(OH)D level. The investigators postulate that the D2 treatment-associated decrease in 25(OH)D3 level may be related to an increase in total 25(OH)D level rather than being specific to D2 treatment, and thus there would be a D3 treatment-associated decrease in 25(OH)D2 level. The investigators plan to conduct a double-blind placebo-controlled trial to examine the effect of D3 treatment on 25(OH)D2 level and the effect of D2 treatment on 25(OH)D3 leve

The effect of vitamin D3 and omega-3 Fatty acids on estradiol levels.

This one-year study will test the hypothesis that supplementation with vitamin D will improve lower extremity muscle performance in older men and women with vitamin D insufficiency.

The purpose of this study is to evaluate the absorption of dietary supplement of vitamin D3 (cholecalciferol), through the variation of 25 (OH) D levels, as the fat content of the meal associated with the administration of the supplement.

Fibroblast growth factor 23 (FGF23) is a newly discovered hormone which regulates phosphate and vitamin D levels. In this study, we are looking at what the normal levels of FGF23 are in adolescent girls and how these levels vary with other hormonal measurements. We will also be looking at whether vitamin D supplementation in adolescents who are deficient in vitamin D alters the levels of FGF23 and other factors including insulin resistance.

Specific Aim 1: To compare effects of Vitamin D supplementation to usual care on symptoms in women transitioning to early postmenopause and determine the associated effect size in order to conduct a power analysis for a future RCT. Hypothesis: Vitamin D insufficient women in early postmenopause who are randomized to supplementation, titrated to achieve sufficiency for 2 months, will have fewer symptoms including hot flashes, mood, and musculoskeletal complaints than women randomized to usual care. Specific Aim 2: To compare effects of Vitamin D supplementation to usual care on body composition (by dual-energy x-ray absorptiometry [DXA] and by weight, BMI, waist to hip ratio) in overweight/obese women transitioning to early postmenopause and determine the associated effect size for a power analysis for a future RCT. Hypothesis: Vitamin D insufficient women in the menopausal transition randomized to supplementation, titrated to achieve sufficiency for 9 months, will improve DXA body composition (less total body and abdominal fat), compared to women in usual care, who will have increased body weight, including total and abdominal fat. Specific Aim 3: To estimate the proportion of overweight/obese middle-aged women who achieve sufficiency by 1 month versus 2 or more months and to determine if achieving sufficiency by 1 month varies by baseline characteristics. Hypothesis: About 80% of participants will achieve sufficient Vitamin D level by 1 month. Those who need more than 1 month for sufficiency will have lower baseline levels and higher initial BMI.

Researchers at the USDA Western Human Nutrition Research Center and clinicians at UC Davis Medical Center are currently conducting a study on the effects of vitamin D supplementation during pregnancy on maternal health and immune function. The investigators believe that vitamin D supplementation at levels greater than the current recommendation is beneficial for maternal health during pregnancy. In particular, there is evidence that vitamin D deficiency during pregnancy puts women at greater risk for diseases like pre-eclampsia, which may be due to an imbalance in immune function at the placenta. This randomized, double-blind study is designed to test this hypothesis. Pregnant women who participate in the study receive either 400 IU or 2,000 IU of vitamin D per day for the duration of their pregnancy. The investigators will collect blood at three time points during pregnancy (16-20 weeks, 26-28 weeks, 36 weeks gestation) for analysis of immune function and vitamin D status. The investigators are also collecting data on clinical parameters, such as blood pressure and glucose tolerance.