BACKGROUND The relative potency of 25-hydroxyvitamin D3 to vitamin D3 needs to be better defined so that food-composition tables can better reflect the true vitamin D nutritive value of certain foods. OBJECTIVE We performed a randomized, controlled intervention study in apparently healthy, free-living adults to investigate whether the intake of 25-hydroxyvitamin D3 is 5 times more potent in r...

BACKGROUND Several observational studies assessed the relationship between serum 25-hydroxyvitamin D [25(OH)D] concentrations and the risk of cancer but results were inconclusive. METHODS We measured 25(OH)D concentrations in a population-based cohort study of 9,949 men and women ages 50 to 74 years in Saarland, Germany. Comprehensively adjusted Cox regression models were applied to estimate ...

OBJECTIVE To investigate relationships between mortality and circulating 25-hydroxyvitamin D (25(OH)D), 25-hydroxycholecalciferol (25(OH)D3) and 25-hydroxyergocalciferol (25(OH)D2). DESIGN Case-cohort study within the Melbourne Collaborative Cohort Study (MCCS). We measured 25(OH)D2 and 25(OH)D3 in archived dried blood spots by LC-MS/MS. Cox regression was used to estimate mortality hazard ra...

In order to obtain a standard compound of 25-hydroxyvitamin D2 (25-OH-D2), a method for isolating in vivo-generated 25-OH-D2 from the blood of rats or rabbits was established by using several steps of preparative high-performance liquid chromatography (HPLC). When the unsaponifiable matter of the plasma obtained from rats or rabbits receiving a large dose of vitamin D2 was applied to the prepar...

25-Hydroxyvitamin D (25(OH)D) half-life is a potential biomarker for investigating vitamin D metabolism and requirements. We performed a pilot study to assess the approach and practical feasibility of measuring 25(OH)D half-life after an oral dose. A total of twelve healthy Gambian men aged 18-23 years were divided into two groups to investigate the rate and timing of (1) absorption and (2) pla...

AIM To describe the characteristics of children with vitamin D deficiency rickets and identify common features and predisposing factors. METHODS A review of the clinical notes of all children less than five years of age with radiological evidence of rickets and serum 25-hydroxyvitamin D levels of less than 10 micrograms/L. Patients were identified by searching all low vitamin D levels perform...