Clinical Question: Does supplementation with vitamin D and calcium prevent a first hip fracture or nonvertebral fracture in older persons?
Setting: Outpatient (any)
Study Design: Meta-analysis (randomized controlled trials)
Synopsis: In this meta-analysis, researchers combined the results of randomized controlled trials evaluating the use of calcium and vitamin D3 in fracture prevention. They searched three databases for studies examining the effect of calcium and vitaminD3 on hip fractures or nonvertebral fractures, searched reference lists and meeting abstracts, and contacted experts. The researchers did not comment on the quality of the studies other than to note that treatment allocation was masked and all but one used an intention-to-treat analysis. Two researchers independently extracted the data from the seven studies, which included 9,820 patients who were 79 years of age on average. Patients lived in the community, in housing for older persons, or in nursing homes, and the majority were women. Hip fracture occurred in a high proportion (7.3 percent) of patients.
The researchers found heterogeneity among the trial results, which was resolved when they separated the studies by dosage of vitamin D. Vitamin D in a dosage of 400 IU per day did not prevent fractures. Vitamin D in dosages of 700 to 800 IU per day resulted in a significant decrease in hip fractures (5.8 versus 7.7 percent), translating into one fewer hip fracture for every 50 patients treated for two years (number needed to treat [NNT] = 50; 95% confidence interval [CI], 34 to 109). Similarly, the nonvertebral fracture rate was decreased only by the higher dosage, with an NNT of 28 (CI, 19 to 49) for at least one year.
Bottom Line: Supplementation with calcium in a dosage of 1,000 mg per day and vitamin D3in a dosage of 800 IU per day decreases the likelihood that older persons will experience a first hip fracture or other nonvertebral fracture. The dosage of calcium is lower than the 1,500 mg daily commonly recommended and used; the vitamin D dosage is higher than that usually used in comparison studies with other drugs. These results conflict with those of two large studies in patients at high risk of fracture or with a previous osteoporotic fracture for whom these dosages did not decrease the rate of fracture (Porthouse J, et al. Randomised controlled trial of calcium and supplementation with cholecalciferol [vitamin D3] for prevention of fractures in primary care. BMJ April 30, 2005;330:1003–6, and Grant AM, et al., for the RECORD Trial Group. Oral vitaminD3 and calcium for secondary prevention of low-trauma fractures in elderly people [Randomised Evaluation of Calcium Or vitamin D, RECORD]: a randomised placebo-controlled trial. Lancet May 7, 2005;365:1621–8). (Level of Evidence: 1a)