Date of release: 08 February, 2010

Vitamin D supplementation for prevention of fractures

Introduction

Comment

Vitamin D deficiency may contribute to increased risk of falls and fractures by causing secondary hyperparathyroidism, bone loss and impaired neuromuscular function. There are conflicting results in some randomized, controlled trials examining the effect of vitamin D on the incidence of fractures. A meta-analysis in 2005 indicated that lower doses (10 µg, 400 IU) were ineffective in preventing fractures [2]. Several recent meta-analyses have also shown that a combination of calcium and vitamin D reduces hip and non-vertebral fractures but vitamin D alone does not [3, 4]. Vitamin D given alone was not shown to be effective [5, 6]; this may have been due to low bioavailability of the preparation, different methods and routes of administration of vitamin D, a long interval between doses, or enrolment of higher-aged women in these studies. Using serum vitamin D levels as a marker for determining the right dose to achieve the recommended target level and maximal efficacy may be the optimal clinical approach. For many people taking 20 µg (800 IU) vitamin D/day may still be a too low dose to achieve the optimal serum levels. Calcium and vitamin D are more effective in decreasing parathyroid hormone levels, improving bone density, and reducing fractures. If calcium is not co-administered, higher doses of vitamin D may be needed to suppress bone turnover. As analysis of individual patient’s data improves the statistical power, the results of the DIPART group become important. I also feel that both calcium and vitamin D be recommended together for the prevention of fractures.

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