Two recent studies suggest that regular supplements of calcium and vitamin D may not effectively prevent fractures. In one study of 5292 patients who had sustained fracture within 3 months, patients received either 1 g of calcium, 20 µg of vitamin D3, both, or placebo. During the study, 698 patients sustained secondary fracture, including 183 hip fractures; however, the rate was similar between all groups, the study showed. These findings, part of the Randomised Evaluation of Calcium or vitamin D (RECORD) trial, appear in Lancet.1
A second study in the British Medical Journal (BMJ) also found no evidence that calcium and vitamin D supplements reduce the risk of fractures in women aged 70 and over with one or more risk factors for hip fracture.2
Taken together, these studies suggest that we should "move more quickly [to antiresorptive drugs] in osteoporotic populations because calcium and vitamin D are essential for bone health, but not enough to strengthen up the bone to reduce fracture risk if you are an at-risk patient," says CIAOMed advisory board member Nancy Lane, MD, associate professor of medicine at the University of California, San Francisco.
In the BMJ study of 3314 women at high risk of hip fracture, a subset of the participants were randomized to receive advice from a practice nurse on how to reduce the risk of fracture, and were given calcium and vitamin D tablets to take daily. The control group received only a leaflet on diet and prevention of falls. All women were monitored for an average of 2 years. Over the monitoring period, fracture rates were lower than expected, but did not significantly differ between the groups, study authors conclude.
"For healthy older people who are living in the community and have a reasonable diet, supplements alone will not be helpful at reducing their fracture risk," author of the BMJ study, David J. Torgerson, PhD, MSc, director of York Trials Unit at the University of York in the UK, tells CIAOMed. "The exception may be people with poor diets, possibly living in institutional care."
The new findings suggest that, in older patients, treatment with biphosphonates, strontium ranelate, or raloxifene may be more effective ways of reducing fracture risk, he suggests.
RECORD data show no reduction in hip fractures with either calcium or vitamin D
"Our trial indicates that routine supplementation with calcium and vitamin D3, either alone or in combination, is not effective in the prevention of further fractures in people who had a recent low-trauma fracture," says RECORD study author Adrian Grant, MA, BM, BCh, director of the Health Services Research Unit at Aberdeen University in the UK.
"Policies for secondary prevention should, therefore, consider other strategies. The main pharmacological intervention is antiresorptive drugs, such as bisphosphonates, which have rarely been assessed in patients who have not been taking calcium or vitamin D."
In an accompanying editorial, Philip Sambrook, FRACP, MD, director and president of the Institute of Bone and Joint Research at the University of Sydney, Australia, points out that interpretation of the RECORD data is made difficult by the poor compliance of the participants. Secondly, the study perpetuates the limitations of most previous studies by measuring 25-hydroxyvitamin D levels in only a small sample. "Thus, the vitamin D status of the trial population at baseline remains largely unknown, although, because the patients were younger than in other studies, ambulatory, and living in the community, they were less likely to have vitamin D deficiency," he writes.
"The data are still consistent with a therapeutic benefit of vitamin D on fractures in people deficient in vitamin D, [but] the effect of vitamin D supplementation in vitamin-D-replete individuals living in the community is less clear," concludes Dr. Sambrook. "Given uncertainties about the efficacy of vitamin D alone or in combination with calcium on falls, more studies of older people with suboptimum vitamin D levels are appropriate to establish benefit on both falls and fracture endpoints."
References:
- Grant AM, Anderson FH. Oral vitamin D3 and calcium for secondary prevention of low-trauma fractures in elderly people (Randomised Evaluation of Calcium Or vitamin D, RECORD): a randomised placebo-controlled study. Lancet. April 28, 2005; [Epub ahead of print].
- Porthouse J, Cockayne S, King C, et al. Randomized controlled trial of supplementation with calcium and cholecalciferol (vitamin D3) for prevention of fractures in primary care. BMJ. 2005;330:1003-1006.