Daily supplements of calcium and vitamin D significantly reduce the risk of fracture, irrespective of age, sex, or previous fractures, concludes a study published on bmj.com today.
However, for vitamin D supplements alone, no significant effects were found.
Fragility fractures are a major cause of illness in older people and a considerable burden to health services; yet conflicting evidence exists on the role of vitamin D, either alone or in combination with calcium, in reducing fractures.
Some studies have shown a reduction in the risk of fractures, others have shown no effect – and one recent study found an increased risk of hip fracture.
The best dose to use; which patients benefit most; and which fractures are most amenable to such treatment remain a clinical dilemma.
So a team of researchers based at Gentofte Hospital in Copenhagen and the University of Southern Denmark analysed data from seven large trials to assess the effectiveness of vitamin D or vitamin D plus calcium in reducing fractures among 68,517 older people (average age 70 years).
They found that vitamin D given alone in doses of 10-20 μg/day is not effective in preventing fractures.
By contrast, calcium and vitamin D given together reduce hip fractures and total fractures, and probably vertebral fractures, irrespective of age, sex, or previous fractures.
The authors emphasise that their analysis does not allow for a direct comparison of vitamin D against vitamin D given with calcium, but only comparisons between each intervention and no treatment. Additional studies of vitamin D are also needed, especially trials of vitamin D given daily at higher doses without calcium, they conclude.