Vitamin D: What is an adequate vitamin D level and how much supplementation is necessary?

Centre on Aging and Mobility, University of Zurich, Department of Rheumatology and Institute of Physical Medicine, Zurich, Switzerland.
Best practice & research. Clinical rheumatology (Impact Factor: 2.6). 12/2009; 23(6):789-95. DOI: 10.1016/j.berh.2009.09.005
Source: PubMed


Strong evidence indicates that many or most adults in the United States and Europe would benefit from vitamin D supplements with respect to fracture and fall prevention, and possibly other public health targets, such as cardiovascular health, diabetes and cancer. This review discusses the amount of vitamin D supplementation needed and a desirable 25-hydroxyvitamin D level to be achieved for optimal musculoskeletal health. Vitamin D modulates fracture risk in two ways: by decreasing falls and increasing bone density. Two most recent meta-analyses of double-blind randomised controlled trials came to the conclusion that vitamin D reduces the risk of falls by 19%, the risk of hip fracture by 18% and the risk of any non-vertebral fracture by 20%; however, this benefit was dose dependent. Fall prevention was only observed in a trial of at least 700 IU vitamin D per day, and fracture prevention required a received dose (treatment dose*adherence) of more than 400 IU vitamin D per day. Anti-fall efficacy started with achieved 25-hydroxyvitamin D levels of at least 60 nmol l(-1) (24 ng ml(-1)) and anti-fracture efficacy started with achieved 25-hydroxyvitamin D levels of at least 75 nmol l(-1) (30 ng ml(-1)) and both endpoints improved further with higher achieved 25-hydroxyvitamin D levels. Founded on these evidence-based data derived from the general older population, vitamin D supplementation should be at least 700-1000 IU per day and taken with good adherence to cover the needs for both fall and fracture prevention. Ideally, the target range for 25-hydroxyvitamin D should be at least 75 nmol l(-1), which may need more than 700-1000 IU vitamin D in individuals with severe vitamin D deficiency or those overweight.

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    • "The Institute of Medicine considers o12 ng/ml of vitamin D as deficient; 12–20 ng/ml insufficient; Z20 ng/ml sufficient, with potential adverse effects at levels 450 ng/ml (Medicine, 2010). Others have reported levels lower than 30 ng/ml to be deficient (Bischoff-Ferrari, 2009), and normal levels to be Z 30 ng/ ml (Carlson and Rose, 2013). 1.2.1. "
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    ABSTRACT: Vitamin D deficiency has been associated with both increased risk and severity of Multiple Sclerosis (MS) as it has a modulating effect on the immune process that causes inflammation/demyelination and axonal damage. Optical Coherence Tomography (OCT) offers a quick, reliable and non-invasive way to assess the Retinal Nerve Fiber Layer (RNFL) and identifies axonal loss generated by either direct inflammation or from neurodegeneration. To determine the association of vitamin D and RNFL in MS patients without a history of Optic Neuritis (ON) by comparing RNFL thickness in patients that are vitamin D deficient with those having normal serum levels. The cohort of 76 MS patients underwent OCT testing to assess the RNFL thickness and macular volume, and measurement of serum 25-OH Vitamin D level. Vitamin D deficiency was defined as <30ng/ml and sufficiency as ≥30ng/ml. A total of 131 eyes were divided in two groups: vitamin D deficient (n=86 eyes, mean=17.7ng/ml) and vitamin D sufficient (n=45 eyes, mean=40.3ng/ml). Twenty one eyes had previous ON and were excluded from this analysis. Vitamin D deficiency was identified in 66% of the participants. RNFL thickness was similar for the vitamin D deficient and sufficient groups (85.5 vs 86μm respectively, p=0.89). Significant differences were present for age with the deficient group being younger (42 years vs 51 years, p=0.005) and having shorter disease duration (7.5 years vs 11.4 years, p=0.006). Vitamin D deficiency is not associated with thinning of RNFL or macular volume in MS eyes unaffected by ON. This finding suggests the role of vitamin D in modulating the severity of MS is not exerted through an influence on neurodegeneration. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.
    Multiple Sclerosis and Related Disorders 07/2014; 3(4). DOI:10.1016/j.msard.2014.03.001 · 0.88 Impact Factor
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    • "Several studies have indicated that the achieved plasma 25OHD concentration, rather than the vitamin D dose given, predicts the effect on bone health [42]. However, measurement of plasma 25OHD, parathyroid hormone (PTH) and other potential markers of vitamin D status have only been performed in a small minority of participants in these intervention studies [41], limiting the ability to explore the relationship between plasma 25OHD concentrations achieved and bone loss and fracture prevention. "
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    ABSTRACT: The randomised, double blind intervention trial 'Optimising Vitamin D Status in Older People' (VDOP) will test the effect of three oral dosages of vitamin D given for one year on bone mineral density (BMD) and biochemical markers of vitamin D metabolism, bone turnover and safety in older people. VDOP is funded by Arthritis Research UK, supported through Newcastle University and MRC Human Nutrition Research and sponsored by the Newcastle upon Tyne Hospitals NHS Foundation Trust#. Vitamin D insufficiency is common in older people and may lead to secondary hyperparathyroidism, bone loss, impairment of muscle function and increased risk of falls and fractures. Vitamin D supplementation trials have yielded conflicting results with regard to decreasing rates of bone loss, falls and fractures and the optimal plasma concentration of 25 hydroxy vitamin D (25OHD) for skeletal health remains unclear.Method/designOlder (>=70 years) community dwelling men and women are recruited through General Practices in Northern England and 375 participants are randomised to take 12,000 international units (IU), 24,000 IU or 48,000 IU of vitamin D3 orally each month for one year starting in the winter or early spring. Hip BMD and anthropometry are measured at baseline and 12 months. Fasting blood samples are collected at baseline and three-month intervals for the measurement of plasma 25OHD, parathyroid hormone (PTH), biochemical markers of bone turnover and biochemistry to assess the dose--response and safety of supplementation. Questionnaire data include falls, fractures, quality of life, adverse events and outcomes, compliance, dietary calcium intake and sunshine exposure. This is the first integrated vitamin D supplementation trial in older men and women using a range of doses given at monthly intervals to assess BMD, plasma 25OHD, PTH and biochemical markers of bone turnover and safety, quality of life and physical performance. We aim to investigate the vitamin D supplementation and plasma 25OHD concentration required to maintain bone health and to develop a set of biochemical markers that reflects the effect of vitamin D on bone. This will aid future studies investigating the effect of vitamin D supplementation on fracture risk.ISRCTN 35648481 (assigned 16 August 2012), EudraCT 2011-004890-10.
    Trials 09/2013; 14(1):299. DOI:10.1186/1745-6215-14-299 · 1.73 Impact Factor
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    • "The primary objective of hypovitaminosis D correction is promoting the maximum intestinal calcium absorption, reducing the frequency of falls and correcting the secondary hyperparathyroidism [27]. According to Bischoff-Ferrari et al., the supplementation with at least 700 IU of vitamin D/d was enough to reduce the risk of vertebral and non-vertebral fractures [34]. Besides that, there are other non-skeletal effects which have been attributed to vitamin D status, such as the prevention of cancer and autoimmune diseases [4]. "
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    ABSTRACT: Background Hypovitaminosis D is a common condition among elderly individuals in temperate-climate countries, with a clear seasonal variation on 25 hydroxyvitamin D [(25(OH)D] levels, increasing after summer and decreasing after winter, but there are few data from sunny countries such as Brazil. We aimed to evaluate 25-hydroxyvitamin D concentrations and its determining factors, in individuals in the city of São Paulo belonging to different age groups and presenting different sun exposure habits. Methods 591 people were included as follows: 177 were living in institutions (NURSING HOMES, NH, 76.2 ± 9.0 years), 243 were individuals from the community (COMMUNITY DWELLINGS, CD, 79.6 ± 5.3 years), 99 were enrolled in physical activity program designed for the elderly (PHYSICAL ACTIVITY, PA, 67.6 ± 5.4 years) and 72 were young (YOUNG, 23.9 ± 2.8 years). Ionized calcium, PTH, 25(OH)D, creatinine and albumin were evaluated. ANOVA, Mann–Whitney and Kruskal Wallis tests, Pearson Linear Correlation and Multiple Regression were used in the statistical analysis. Results 25(OH)D mean values during winter for the different groups were 36.1 ± 21.2 nmol/L (NH), 44.1 ± 24.0 nmol/L (CD), 78.9 ± 30.9 nmol/L (PA) and 69.6 ± 26.2 nmol/L (YOUNG) (p < 0.001) while during summer they were 42.1 ± 25.9 nmol/L, 59.1 ± 29.6 nmol/L, 91.6 ± 31.7 nmol/L and 103.6 ± 29.3 nmol/L, respectively (p < 0.001). The equation which predicts PTH values based on 25(OH)D concentration is PTH = 10 + 104.24.e-(vitD-12.5)/62.36 and the 25(OH)D value above which correlation with PTH is lost is 75.0 nmol/L. In a multiple regression analysis having 25(OH)D concentration as the depending variable, the determining factors were PTH, ionized calcium and month of the year (p < 0.05). Conclusions Much lower 25(OH)D values were found for the older individuals when compared to younger individuals. This finding is possibly due to age and habit-related differences in sunlight exposure. The existence of seasonal effects on 25(OH)D concentration throughout the year was evident for all the groups studied, except for the nursing home group. According to our data, PTH values tend to plateau above 75 nmol/L.
    BMC Endocrine Disorders 04/2013; 13(1):14. DOI:10.1186/1472-6823-13-14 · 1.71 Impact Factor
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