Article

Vitamin D: Bone and Beyond, Rationale and Recommendations for Supplementation

Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Fla, USA.
The American journal of medicine (Impact Factor: 5.3). 10/2009; 122(9):793-802. DOI: 10.1016/j.amjmed.2009.02.029
Source: PubMed

ABSTRACT Adequate vitamin D status is necessary and beneficial for health, although deficiency plagues much of the world's population. In addition to reducing the risk for bone disease, vitamin D plays a role in reduction of falls, as well as decreases in pain, autoimmune diseases, cancer, heart disease, mortality, and cognitive function. On the basis of this emerging understanding, improving patients' vitamin D status has become an essential aspect of primary care. Although some have suggested increased sun exposure to increase serum vitamin D levels, this has the potential to induce photoaging and skin cancer, especially in patients at risk for these conditions. Vitamin D deficiency and insufficiency can be both corrected and prevented safely through supplementation.

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    • "Indeed, recent studies have shown that several tissues, in addition to the kidneys, express the enzyme CYP27B1, which catalyzes the 1í µí»¼-hydroxylation of 25(OH)D, and that the vitamin D receptor (VDR) is expressed ubiquitously [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]. It is now known that a conversion of 25(OH)D to 1í µí»¼,25-dihydroxyvitamin D (calcitriol, the active form of vitamin D) occurs in several extrarenal cells and may be associated with significant biological roles beyond those traditionally attributed to vitamin D [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]. "
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    ABSTRACT: The aim of the present study was to evaluate the dose of postdialysis cholecalciferol needed to maintain the 25-hydroxyvitamin D [25(OH)D] levels in the optimal range of 75-150 nmol/L. Twenty-six patients who had low baseline 25(OH)D levels (mean 27.5 ± 14.9 nmol/L) were studied. The 25(OH)D levels were measured every 2 months for one year. During the first two months, all the patients received 2000 IU of cholecalciferol after each hemodialysis (=6000 IU/wk). Thereafter, the dose was individualized and adapted every 2 months by administering 1 to 6 cholecalciferol tablets (2000 IU each) per week (total weekly dose = 2000-12000 IU/wk). During cholecalciferol supplementation, the 25(OH)D concentrations rapidly increased from baseline to 140.1 ± 28.3 nmol/L at month 6 and 95.6 ± 20.9 nmol/L at month 12. At month twelve, 86% of the patients had 25(OH)D levels within the target range with a mean dose of 5917 ± 4106 IU/wk of cholecalciferol; however, the amount needed to maintain these levels varied widely from 0 (n = 2) to 12000 IU/wk (n = 5). In conclusion, postdialysis cholecalciferol prescription is quite effective in correcting vitamin D deficiency/insufficiency, but the amount of cholecalciferol needed to maintain the 25(OH)D levels within the optimal range over the long-term varies widely among patients and must be individualized.
    01/2014; 2014:597429. DOI:10.1155/2014/597429
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    • "Besides its well-established roles in mineral homeostasis and bone metabolism, an ever-increasing body of evidence indicates that vitamin D is also involved in the regulation of cell proliferation, inflammation and anti-microbial defence [1] [2] [3]. Observational and epidemiological studies have demonstrated close associations between vitamin D status and conditions such as osteoporosis, cancer, autoimmune, cardiovascular and infectious diseases [4] [5] [6] [7]. A recent study estimates that worldwide approximately one billion individuals would be classified as either vitamin D deficient or insufficient [8]. "
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    ABSTRACT: The accurate measurement of 25-hydoxy vitamin D (25OH-D) in serum has been a challenge for many years. We developed a liquid chromatography tandem mass spectrometry (LC Tandem MS) assay for the quantitative determination of 25OH-D(2) and 25OH-D(3) in serum. The new method was compared with two widely used commercially available immunoassays. Sample preparation involved protein precipitation with acetonitrile containing deuterated forms of the target species as internal standards. An API 5000 mass spectrometer coupled with a photoionization source was used for quantitation. The performance of the new LC Tandem MS assay was compared with a radioimmunoassay (RIA, Diasorin) and a chemiluminescence immunoassay (ECLIA, Roche Diagnostics), analysing serum obtained from 152 individuals. Using 100 μl of serum, the LC Tandem MS assay had a limit of quantitation of 1.3 nmol/L for both 25OH-D(2) and 25OH-D(3) with a linear response between 1.3 and 625 nmol/L and accuracy of between 95 and 124%. Intra- and inter-assay precision were ≤7% and ≤4%, respectively. Measurement of 25OH-D levels in 152 serum samples gave run averages of 71, 56 and 62 nmol/L for LC Tandem MS, ECLIA and RIA, respectively. Correlations between the various methods were: LC Tandem MS vs. RIA: r=0.931; LC Tandem MS vs. ECLIA: r=0.784; RIA vs. ECLIA: r=0.787. The LC Tandem MS method had a positive proportional bias of 26% over the RIA, whereas the ECLIA showed variable differences. The new LC Tandem MS assay is accurate and precise at physiologically relevant 25OH-D concentrations, and compares favourably with the RIA. In contrast, the ECLIA shows variable bias with the other assays tested.
    Steroids 12/2010; 75(13-14):1106-12. DOI:10.1016/j.steroids.2010.07.006 · 2.72 Impact Factor
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    • "Hypovitaminosis D in multiple sclerosis Brain 2010: 133; 1869–1888 | 1873 suggesting a lack of vitamin D in all these intermediate age groups, a chronic vitamin D insufficiency could have pernicious delayed effects on the development of osteoporosis and a wide range of serious diseases. Therefore, during the past few years, a growing part of the medical community has advocated a systematic supplementation, at least during winter, for the general population living in temperate or Nordic countries (Holick, 2004; Hollis, 2005; Vieth, 2006; Binkley, 2009; Cavalier et al., 2009; Edlich et al., 2009; Grant et al., 2009; Stechschulte et al., 2009; Gillie, 2010; Zittermann et al., 2010). To sum up these historical aspects, it took almost a century to understand that rickets observed in infants in Northern industrial countries was due to vitamin D deficiency, and it has now taken almost another century to realize that all age groups in these countries suffer from a lack of vitamin D. "
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    ABSTRACT: The role of hypovitaminosis D as a possible risk factor for multiple sclerosis is reviewed. First, it is emphasized that hypovitaminosis D could be only one of the risk factors for multiple sclerosis and that numerous other environmental and genetic risk factors appear to interact and combine to trigger the disease. Secondly, the classical physiological notions about vitamin D have recently been challenged and the main new findings are summarized. This vitamin could have an important immunological role involving a number of organs and pathologies, including autoimmune diseases and multiple sclerosis. Furthermore, human requirements for this vitamin are much higher than previously thought, and in medium- or high-latitude countries, they might not be met in the majority of the general population due to a lack of sunshine and an increasingly urbanized lifestyle. Thereafter, the different types of studies that have helped to implicate hypovitaminosis D as a risk factor for multiple sclerosis are reviewed. In experimental autoimmune encephalomyelitis, vitamin D has been shown to play a significant immunological role. Diverse epidemiological studies suggest that a direct chain of causality exists in the general population between latitude, exposure to the sun, vitamin D status and the risk of multiple sclerosis. New epidemiological analyses from France support the existence of this chain of links. Recently reported immunological findings in patients with multiple sclerosis have consistently shown that vitamin D significantly influences regulatory T lymphocyte cells, whose role is well known in the pathogenesis of the disease. Lastly, in a number of studies on serum levels of vitamin D in multiple sclerosis, an insufficiency was observed in the great majority of patients, including at the earliest stages of the disease. The questionable specificity and significance of such results is detailed here. Based on a final global analysis of the cumulative significance of these different types of findings, it would appear likely that hypovitaminosis D is one of the risk factors for multiple sclerosis.
    Brain 07/2010; 133(Pt 7):1869-88. DOI:10.1093/brain/awq147 · 10.23 Impact Factor
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