Learn More
Maternal vitamin D deficiency during pregnancy is a recognized risk factor for rickets and osteomalacia in infancy (1). The circulating plasma concentration of 25-hydroxyvitamin D (25OHD), a long-lived metabolite of vitamin D, is used to judge vitamin D status; values below 25 nmol ⁄ L are associated with an increased risk of rickets and osteomalacia (1).(More)
Vitamin D is an important determinant of bone health at all ages. The plasma concentrations of 25-hydroxy vitamin D (25-OH D) and other metabolites are used as biomarkers for vitamin sufficiency and function. To allow for the simultaneous determination of five vitamin D metabolites, 25-OH D(3), 25-OH D(2), 24,25-(OH)(2) D(3), 1,25-(OH)(2) D(3), and(More)
CONTEXT There is uncertainty over the equivalence of vitamins D2 and D3 to maintain plasma 25-hydroxyvitamin D (25(OH)D). OBJECTIVE The objective of the study was to compare the plasma half-lives of 25(OH)D2 and 25(OH)D3 in two distinct populations with different dietary calcium intake and 25(OH)D status. PARTICIPANTS Healthy men (aged 24 and 39 y),(More)
UNLABELLED Predictors of 25(OH)D3 half-life were factors associated with vitamin D metabolism, but were different between people in The Gambia and the UK. Country was the strongest predictor of plasma 25(OH)D concentration, probably as a marker of UVB exposure. 25(OH)D3 half-life may be applied as a tool to investigate vitamin D expenditure. INTRODUCTION(More)
In this issue of the British Journal of Nutrition, Islam et al. and Woo et al. (2) present data from Bangladesh and China showing a high prevalence of poor vitamin D status in women of childbearing age combined with a concurrent elevation in plasma parathyroid hormone (PTH) concentration. These reports add to the growing evidence of a high prevalence of(More)
UNLABELLED Use of hormonal contraceptives (HC) may influence total plasma concentrations of vitamin D metabolites. A likely cause is an increased synthesis of vitamin D binding protein (VDBP). Discrepant results are reported on whether the use of HC affects free concentrations of vitamin D metabolites. AIM In a cross-sectional study, plasma concentrations(More)
Africa is heterogeneous in latitude, geography, climate, food availability, religious and cultural practices, and skin pigmentation. It is expected, therefore, that prevalence of vitamin D deficiency varies widely, in line with influences on skin exposure to UVB sunshine. Furthermore, low calcium intakes and heavy burden of infectious disease common in many(More)
Ethnic differences in bone metabolism have been reported and it has been suggested that these may be partly due to prolonged exposure to an elevated plasma parathyroid hormone (PTH) concentration or a decreased sensitivity to PTH. We explored ethnic differences in bone and mineral metabolism by 5 days of oral phosphate (P) loading to stimulate PTH(More)
Parathyroid hormone (PTH) is used as a marker of vitamin D (VD) status. However, PTH depends on many other factors. The 24,25-dihydroxy VD (24,25VD) concentration may be a sensitive marker because its production is reduced in VD deficiency. The relationship between VD metabolites, their ratio and PTH was investigated in adolescents from the UK and The(More)
UNLABELLED MAVIDOS is a randomised, double-blind, placebo-controlled trial (ISRCTN82927713, registered 2008 Apr 11), funded by Arthritis Research UK, MRC, Bupa Foundation and NIHR. BACKGROUND Osteoporosis is a major public health problem as a result of associated fragility fractures. Skeletal strength increases from birth to a peak in early adulthood.(More)