Does vitamin D increase the risk of fractures?

From the Guidelines

Vitamin D does not increase the risk of fractures, but rather helps to prevent them. According to a meta-analysis of 12 double-blind RCTs, vitamin D supplementation has been shown to reduce the risk of non-vertebral fractures by 20% and hip fractures by 18% in individuals ≥ 65 years old, with a high received dose of vitamin D (482-770 IU/day or 12.0-19.25 μg/day) and achieved blood 25(OH)D levels of at least 30 to 40 ng/ml 1.

Key Points

• Vitamin D has a dual benefit for prevention of fractures in the elderly, a benefit on bone density and muscle strength 1.
• A meta-analysis of 8 double-blind RCTs demonstrated that falling was significantly reduced by 13% in vitamin D supplemented individuals compared with those receiving placebo 1.
• The recommended daily intake of vitamin D is 600-800 IU for most adults, with higher doses (up to 1000-2000 IU per day) potentially necessary for individuals at risk of deficiency, under medical supervision.
• Vitamin D can be obtained through sun exposure, diet (fatty fish, egg yolks, fortified foods), or supplements, and it is essential to maintain adequate levels throughout the year, especially in regions with limited sunlight.

Important Considerations

• A blood test can determine vitamin D levels and assess the need for supplementation, and individuals with a history of fractures or osteoporosis should consult their doctor for personalized recommendations.
• The heterogeneity of the studies highlights the importance of considering factors such as dose and achieved blood 25(OH)D levels when evaluating the anti-fracture efficacy of vitamin D supplementation 1.

From the Research

Vitamin D and Fracture Risk

• The relationship between vitamin D and fracture risk is complex, with some studies suggesting that high doses of vitamin D may actually increase the risk of fractures 2.
• A systematic review and meta-analysis found that vitamin D supplementation had no effect on total fracture, hip fracture, or falls, and that high-dose vitamin D supplementation may even increase the risk of hip fractures 3.
• Another study suggested that vitamin D supplementation could have a U-shaped effect on fracture risk, with both low and high doses of vitamin D increasing the risk of fractures 2.

Vitamin D Deficiency and Fracture Risk

• Vitamin D deficiency has been shown to increase the risk of fractures, particularly in older adults, by causing secondary hyperparathyroidism and increasing bone resorption 4, 5.
• Vitamin D deficiency can also cause osteomalacia, a painful bone disease that increases the risk of fractures 4, 6.
• Maintaining adequate vitamin D levels is important for maximizing bone health and preventing fractures, but vitamin D supplementation may not be effective in preventing fractures in individuals with adequate vitamin D levels 3, 2.

Optimal Vitamin D Levels and Fracture Prevention

• The optimal level of vitamin D for fracture prevention is not well established, but most studies suggest that a serum 25-hydroxyvitamin D level of at least 30 ng/mL is necessary for maximum bone health 4, 6.
• The Endocrine Society recommends that adults maintain a circulating concentration of 25-hydroxyvitamin D of at least 30 ng/mL for maximum bone health 4.
• Vitamin D supplementation may be effective in preventing fractures in individuals with severe vitamin D deficiency, but the evidence is not consistent and more research is needed to determine the optimal dose and duration of supplementation 2, 6.