Where do we stand on vitamin D?
Section snippets
Available evidence from primary prevention high quality trials and rational of a proposed fracture efficacy threshold at 75 nmol/l 25-hydroxyvitamin D
In a recent quasi-consensus of vitamin D experts (5 out of 6), a threshold of 75 nmol/l was proposed as the serum 25(OH)D concentration at which older men and women will be at a lower risk of fracture [1]. This standard was supported by a recent meta-analysis of primary prevention high-quality trials (n = 9829) where 700–800 IU D3 per day (with or without calcium supplementation) reduced the relative risk (RR) of hip fracture by 26% (pooled RR = 0.74; 95% CI [0.61,0.88]) and any non-vertebral
Limitations of recent trials that used D3
Table 1 summarized details of recent trials. Two trials tested 800 IU D3 with 1000 mg calcium per day [12], [13], 2 trials tested 400 IU D3 plus 1000 mg calcium [14], [15], and 2 trials tested D2 in high intermittent doses (300,000 IU by intra-muscular injection [16], [17], or oral 100,000 IU every 3 months) [18]. All but one trial [17] showed negative results in the intent-to-treat analysis. And the one trial with positive findings does not qualify as a high-quality trial due to its
Limitations of recent pragmatic trials that used D2
There is increasing literature on the relative disproportionate potency of supplemental D2 compared to D3 as summarized in a recent review by Drs. Houghton and Vieth [21]. Although still regarded as equivalent, several recent studies indicate that their abilities to raise serum 25(OH)D serum levels differ significantly, especially if applied in large intermittent doses. Armas et al. demonstrated that 50,000 IU oral D2 produce a similar rise in serum 25(OH)D levels at Day 3 after the application
Summary and future research in vitamin D
Based on findings from recent trials discussed in this review, two questions appear important to be addressed in future trials with D3: (1) What is the optimal dose of D3 that will bring most individuals up to 75 nmol/l 25-hydroxyvitamin D where optimal bone density, optimal lower extremity strength, fall prevention, and fracture efficacy is expected, and (2) what are alternative dosing strategies that could improve adherence to supplementation with D3. Due to the relatively lower potency of D2
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Cited by (33)
Prevalence of vitamin D inadequacy in European women aged over 80 years
2014, Archives of Gerontology and GeriatricsCitation Excerpt :Interestingly, in our study, women taking the vitamin D supplementation had a higher 25(OH)D level compared to women without supplementation. If a meta-analysis has shown a 22% reduction in falls with vitamin D supplementation (Bischoff-Ferrari et al., 2004), it should be pointed out that the exact role of vitamin D supplementation on fracture prevention is still debated (Bischoff-Ferrari & Dawson-Hughes, 2007; Bischoff-Ferrari et al., 2005; Grant et al., 2005; Jackson et al., 2006; Kanis et al., 2008; Law, Withers, Morris, & Anderson, 2006; Porthouse et al., 2005; Rizzoli et al., 2008; Vieth et al., 2007) even if some recent data suggest a clinically relevant effect of vitamin D at the level of at least 800 IU per day combined with calcium supplementation. It should also be pointed out that vitamin D repletion appears to be a prerequisite for maximizing the response to anti-osteoporotic treatment in terms of both bone mineral density changes and anti-fracture efficacy (Adami et al., 2009; Deane, Constancio, Fogelman, & Hampson, 2007; Geller, Hu, Reed, Mirocha, & Adams, 2008).
Impact of vitamin D supplementation during a resistance training intervention on body composition, muscle function, and glucose tolerance in overweight and obese adults
2013, Clinical NutritionCitation Excerpt :It is clear that attainment of optimal muscle mass is important to health as greater lean mass is associated with improved insulin sensitivity and reduced risk for obesity.1,2 In addition, improved muscle function is associated with reduced falls, subsequent bone fractures and associated sequelae.3 It has been shown that vitamin D contributes to the improvement of bone health independent of calcium regulation.
Supplementation With Vitamin D and Calcium in Long-Term Care Residents
2011, Journal of the American Medical Directors Association25-OH-Vitamin D assay variation and subject management in clinical practice
2010, Clinical BiochemistryStrategies for treatment to prevent fragility fractures in postmenopausal women
2009, Best Practice and Research: Clinical RheumatologyCitation Excerpt :In the context of osteoporosis, falls and fractures, vitamin D plays a role in skeleton health (such as in calcium absorption and bone mineralisation) and in extraskeletal tissues (such as muscle). Fracture prevention has been demonstrated when serum levels above 75 nmol l-1 were achieved [38]. Fall reduction has been found with doses of 700–800 IU day–1. [38]