Vitamin D and vitamin D analogues for preventing fractures associated with involutional and post-menopausal osteoporosis

  • Review
  • Intervention

Authors


Abstract

Background

Vitamin D and related compounds have been used to prevent osteoporotic fractures in older people.

Objectives

To determine the effects of vitamin D or related compounds, with or without calcium, for preventing fractures in older people.

Search strategy

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, the Cochrane Central Register of Controlled Trials (The Cochrane Library 2007, Issue 3), MEDLINE, EMBASE, CINAHL, and reference lists of articles. Most recent search: October 2007.

Selection criteria

Randomised or quasi-randomised trials comparing vitamin D or related compounds, alone or with calcium, against placebo, no intervention, or calcium alone, reporting fracture outcomes in older people.

Data collection and analysis

Two authors independently assessed trial quality, and extracted data. Data were pooled, where admissible, using the fixed-effect model, or random-effects model if heterogeneity between studies appeared high.

Main results

Forty-five trials were included.

Vitamin D alone appears unlikely to be effective in preventing hip fracture (nine trials, 24,749 participants, RR 1.15, 95% CI 0.99 to 1.33), vertebral fracture (five trials, 9138 participants, RR 0.90, 95% CI 0.42 to 1.92) or any new fracture (10 trials, 25,016 participants, RR 1.01, 95% CI 0.93 to 1.09).

Vitamin D with calcium reduces hip fractures (eight trials, 46,658 participants, RR 0.84, 95% CI 0.73 to 0.96). Although subgroup analysis by residential status showed a significant reduction in hip fractures in people in institutional care, the difference between this and the community-dwelling subgroup was not significant (P = 0.15).

Overall hypercalcaemia is significantly more common in people receiving vitamin D or an analogue, with or without calcium (18 trials, 11,346 participants, RR 2.35, 95% CI 1.59 to 3.47); this is especially true of calcitriol (four trials, 988 participants, RR 4.41, 95% CI 2.14 to 9.09). There is a modest increase in gastrointestinal symptoms (11 trials, 47,042 participants, RR 1.04, 95% CI 1.00 to 1.08, P = 0.04) and a small but significant increase in renal disease (11 trials, 46,537 participants, RR 1.16, 95% CI 1.02 to 1.33).

Authors' conclusions

Frail older people confined to institutions may sustain fewer hip fractures if given vitamin D with calcium. Vitamin D alone is unlikely to prevent fracture. Overall there is a small but significant increase in gastrointestinal symptoms and renal disease associated with vitamin D or its analogues. Calcitriol is associated with an increased incidence of hypercalcaemia.

Plain language summary

Vitamin D and related vitamin D compounds for preventing fractures resulting from osteoporosis in older people.

Vitamin D is necessary for building bone. Older people often have low vitamin D levels through lack of exposure to sunlight and low dietary intake. Therefore, it has been suggested that taking additional vitamin D supplements may help to reduce the risk of hip and other fractures, which are very common in older people.

This review included 45 trials with 84,585 participants. The review found that taking vitamin D alone is unlikely to prevent fracture. Vitamin D taken with additional calcium supplements does appear to reduce risk of hip fractures in people living in institutional care. Although the risk of harmful effects from vitamin D and calcium is small, some people, particularly with kidney stones, kidney disease or high blood calcium, should seek medical advice before taking these supplements.

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