OBJECTIVE Poor nutrition and limited sunlight exposure (season) can be related to reduced serum 25-hydroxyvitamin D (25(OH)D) concentrations. Thus, elderly people in the Nordic countries might be at high risk for vitamin D deficiency. The aims of the study were to describe the prevalence of vitamin D deficiency in elderly hospitalized patients in Reykjavik, Iceland, and to investigate the effec...

1α,25-Dihydroxyvitamin D3 [1α,25(OH)2D3] is a steroid hormone derived from circulating 25(OH) vitamin D [25(OH)D] with chemopreventive effects in colorectal cancer. 1α,25(OH)2D3 acts through transcriptional mechanisms; however, our understanding of vitamin D transcriptional responses in the colon is derived from studies in transformed cancer cell lines which may not represent responses in norma...

Both lower serum 25-hydroxyvitamin D [25(OH)D] and elevated homocysteine concentrations are potential risk factors for cardiovascular disease (CVD). A recent analysis of the National Health and Nutrition Examination Survey reported an inverse association of serum 25(OH)D with homocysteine, however, the longitudinal relationship has yet to be investigated. We hypothesized and examined whether a ...

there are some reports of decreased serum levels of 25(oh)d in the subjects with impaired glucose tolerance and type 2 diabetes mellitus (t2dm). to assess vitamin d status of the iranian diabetics, a pilot study was conducted on 90 subjects with either type 1 diabetes mellitus (t1dm) (n= 30), t2dm (n= 30), or apparently healthy subjects (n= 30) during fall and winter of 2005. serum samples were...

Introduction: In serum, 25-hydroxy-vitamin D (25(OH)D) can be found in two forms, namely 25(OH)D2 and 25(OH)D3. We recently published a mathematical method to estimate the 25(OH)D2 recovery without spiking the samples. Since then, new “total” vitamin D immunoassays have appeared on the market (Roche “Total” vitamin D, Siemens Centaur vitamin D “total”, “total” vitamin D on DiaSorin Liaison XL, ...

This article describes the in vitro and in vivo effects of a 25-hydroxycholecalciferol (25[OH]D) treatment in layer hens during a mixed coccidia challenge. HD11 cells (chicken macrophage cell line) were treated in vitro with a coccidia antigen or in a medium supplemented with either 1,25-dihydroxycholecalciferol (1,25[OH]2D) or 25(OH)D. HD11 cells treated in vitro with 200 nM of 1,25(OH)2D had ...

BACKGROUND As published data on 25-hydroxy-cholecalciferol (25(OH)D) deficiency in primary care settings is scarce, we assessed the prevalence of hypovitaminosis D, potential associations with clinical symptoms, body mass index, age, Vitamin D intake, and skin type in unselected patients from primary care, and the extent of seasonal variations of serum 25(OH)D concentrations. METHODOLOGY/PRIN...

BACKGROUND/OBJECTIVES Vitamin D deficiency is common in hemodialysis patients. The aim of this study was to identify whether or not sun exposure and dietary vitamin D intake have effects on serum 25-hydroxyvitamin D (25(OH)D) status in hemodialysis (HD) patients. The objective was to identify the main determinants of serum vitamin D status in the study subjects. SUBJECTS/METHODS A cross-secti...

In all species tested, except humans, biological differences between vitamins D2 and D3 are accepted as fact. To test the presumption of equivalence in humans, we compared the ability of equal molar quantities of vitamin D2 or D3 to increase serum 25-hydroxyvitamin D [25(OH)D], the measure of vitamin D nutrition. Subjects took 260 nmol (approximately 4000 IU) vitamin D2 (n=17) or vitamin D3 (n=...

BACKGROUND The effect of assay drifts over time on serum 25-hydroxyvitamin D [25(OH)D] concentrations were not accounted for in previous national survey studies. Thus, previously reported associations between 25(OH)D with cardiometabolic risk factors using data from NHANES were likely over- or underestimated. Moreover, associations between serum 25(OH)D and metabolic syndrome (MetSyn), insulin ...