BACKGROUND Low serum 25-hydroxyvitamin D ¿25(OH)D concentrations are commonly found in the elderly and are associated with hip fracture. Treatment with vitamin D and calcium can reduce the risk of fracture. The relation between the rise in parathyroid hormone (PTH) with age and the decrease in 25(OH)D is not clear. Neither is there any consensus on the serum concentration of 25(OH)D required fo...

BACKGROUND It is not known whether genetic variation in the vitamin D binding protein (DBP) influences 25-hydroxyvitamin D levels [25(OH)D] after vitamin D supplementation. We aimed to investigate the changes of total 25(OH)D, 25(OH)D₃ and 25(OH)D₂ in a Thai cohort, according to type of vitamin D supplement (vitamin D₃ or D₂) and DBP genotype, after receiving vitamin D₃ or D₂ for 3 months. ME...

Vitamin D has been hypothesized to reduce risk of pregnancy complications such as preeclampsia, gestational diabetes mellitus, and preterm delivery. However, many of these outcomes are rare and require a large sample size to study, representing a challenge for cohorts with a limited number of preserved samples. The aims of this study were to (1) identify predictors of serum 25-hydroxy-vitamin D...

Cholangiocarcinoma (CCA) is a devastating disease without effective treatments. 1α,25(OH)₂D₃, the active form of Vitamin D, has emerged as a new anti-cancer regimen. However, the side effect of hypercalcemia impedes its systemic administration. 25(OH)D is biologically inert and needs hydroxylation by CYP27B1 to form 1α,25(OH)₂D₃, which is originally believed to only take place in kidneys. Recen...

OBJECTIVE The precise incidence of vitamin D deficiency is not known, primarily because there is no consensus on the optimal levels of serum 25(OH)Vitamin D. The aim of the present study was to determine the incidence of vitamin D deficiency in a large group of normal adult volunteers residing in a typical temperate region. DESIGN-METHODS: In 625 healthy, free living adults (553 women, 72 men, ...

Some studies suggested that adequate vitamin D might reduce inflammation in adults. However, little is known about this association in early life. We aimed to determine the relationship between cord blood 25-hydroxyvitamin D (25(OH)D) and C-reactive protein (CRP) in neonates. Cord blood levels of 25(OH)D and CRP were measured in 1491 neonates in Hefei, China. Potential confounders including mat...

BACKGROUND Interactions between calcium and vitamin D may have implications for the regulation of serum 25-hydroxyvitamin D [25(OH)D] and its catabolism and, consequently, the vitamin D dietary requirement. OBJECTIVE We investigated whether different calcium intakes influenced serum 25(OH)D and indexes of vitamin D activation and catabolism during winter and in the context of both adequate an...

BACKGROUND 25 (OH) vitamin D3 (25(OH)D) and parathyroid hormone (PTH) are important regulators of calcium homeostasis. The aim of this study was to retrospectively determine the cut-off for sufficient 25(OH)D in a four-season region and the influence of age, seasons, and gender on serum 25(OH)D and PTH levels. METHODS Laboratory results of 9890 female and 2723 male individuals aged 38.8±22.1 ...

background: the most reliable indicator of vitamin d status is circulating concentration of 25‑hydroxycalciferol (25(oh) d) routinely determined by enzyme‑immunoassays (eia) methods. this study was performed to compare commonly used competitive protein‑binding assays (cpba)‑based eia with the gold standard, high‑pressure liquid chromatography (hplc). methods: concentrations of 25(oh) d in sera ...