CONTEXT A number of controversies exist regarding appropriate treatment strategy for Vitamin D deficiency. AIMS The aim of this study was to investigate the efficacy of equivalent doses of oral cholecalciferol (60,000 IU weekly for 5 weeks) versus intramuscular (IM) cholecalciferol (300,000 IU) in correcting Vitamin D deficiency in apparently healthy volunteers working in a hospital. SETTIN...

Although the biological requirement for vitamin D can be met by epidermal exposure to UV light, there are a number of conditions where this production does not occur or is not sufficient to meet biological needs. When this happens, vitamin D must be consumed and is a nutrient. However, two distinct observations have caused researchers to rethink certain dogma in vitamin D biology. First, it app...

BACKGROUND Vitamin D status generally varies seasonally with changing solar UVB radiation, time in the sun, amount of skin exposed, and, possibly, diet. The Seasonal D Study was designed to quantify the amplitude and phase of seasonal variation in the serum concentration of 25-hydroxyvitamin D, (25OH)D)) and identify the determinants of the amplitude and phase and those of inter-individual vari...

Background & Aims: Serum 25-hydroxyvitamin D (25(OH)D) comprises 25(OH)D3 and 25(OH)D2. Although sex differences in 25(OH)D levels have been reported, it remains unclear whether the difference lies profiles of 25(OH)D. We determined serum 25(OH)D3, 25(OH)D2, 3-epi-25-hydroxyvitamin D3 (3-epi-25(OH)D3), (24R)-24,25-dihydroxyvitamin (24,25(OH)2D3) measured by LC-MS/MS healthy adults not consuming...

BACKGROUND Inadequate vitamin D status is common in many populations around the world. OBJECTIVE The aim was to evaluate potentially modifiable determinants of vitamin D status in an older population. DESIGN This was a cross-sectional study from a population-based cohort including 538 white Dutch men and women aged 60-87 y. Vitamin D status was assessed by plasma 25-hydroxyvitamin D [25(OH)...