View clinical trials related to 25-hydroxyvitamin D Concentration (Vitamin D Status).
Filter by: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
Vitamin D insufficiency has become a global concern, with low vitamin D status associated with bone disorders, cardiovascular disease and certain cancers. The United Kingdom (UK) and Ireland are at particular risk of vitamin D deficiency owing to the northerly latitude, increased use of sunscreen, decreased sun exposure and a high level of cloud cover. A recent survey in the UK showed that more than 50% of UK adults have insufficient vitamin D status, with lower levels noted in the winter months. Variations in vitamin D status have been known to vary between summer and winter, owing to our northern latitude (52-55°N) the Ultraviolet (UV)-B intensity in Northern Ireland is inadequate to promote the dermal synthesis of vitamin D during the winter months, causing us to rely on dietary sources. The aim of this intervention is to investigate the main effects of vitamin D3-fortified milk and supplemental vitamin D3 on vitamin D status and functional health outcomes during the winter, and how this intervention will affect subsequent dermal synthesis of vitamin D from UV exposure. Participants will be recruited from the local community. Blood samples will be collected from each participant at two timepoints (September/October and March/April). Pre- and post-intervention blood pressure, grip strength, height, weight, waist and hip circumferences will be measured, in addition participants will undergo a dual energy x-ray absorptiometry (DXA) scan to assess body composition and bone mineral density. Information on general health, lifestyle, physical activity, dietary intake and typical behaviours in the sun will be collected. Following the dietary intervention, a subset of participants will be invited to participate in a follow-up study, examining UV exposure during the summer months, when they will wear a personal wrist dosimeter for 1 month, complete a sun dairy and provide 2 additional blood samples.
Prevalence of VDD is high worldwide, even in sunbathed equatorial regions where it had not been suspected before. The most cost-effective method for reducing population-wide VDD is through fortification of commonly consumed foods. Nevertheless, the efficacy of fortification varies by dose, duration, and population characteristics; and it is currently unknown whether it could be an efficacious public health intervention to curb the VDD epidemic among children living in tropical areas. We propose to conduct a randomized, controlled, double blind trial to assess the effect of vitamin D3 fortification of milk on serum 25-hydroxyvitamin D concentrations in school-age children and their mothers in Bogotá, Colombia. Eighty families with a child participating in an ongoing cohort study will be randomized to receive one liter per day of either skim milk fortified with 600 IU vitamin D3 per 250mL or unfortified skim milk for a six-week period. Caregivers will be instructed to give the index child two cups of milk per day and to distribute the remaining milk to the rest of the family. We will measure serum 25(OH)D concentrations of the children and mothers at baseline and at the end of the intervention period.