Calcium and vitamin D supplementation did not reduce fractures in women ≥ 70 years of agePDF
ACP J Club. 2005 Nov-Dec;143:73. doi:10.7326/ACPJC-2005-143-3-073
Related Content in this Issue
• Companion Abstract and Commentary: Review: 700 to 800 IU/d of vitamin D reduces hip and nonvertebral fractures in older persons and Vitamin D3, calcium, or both did not prevent secondary fractures in elderly people
Clinical Impact Ratings
Porthouse J, Cockayne S, King C, et al. Randomised controlled trial of calcium and suplementation with cholecalciferol (vitamin D3) for prevention of fractures in primary care. BMJ. 2005;330:1003. [PubMed ID: 15860827]
Do calcium and vitamin D reduce the risk for fracture in at-risk community-dwelling older women?
Design: Randomized controlled trial.
Follow-up period: Median 25 months.
Setting: Nurse-led clinics in England, UK.
Patients: 3454 women ≥ 70 years of age (mean age 77 y) with ≥ 1 risk factor for hip fracture (body weight < 58 kg, previous fracture, maternal history of hip fracture, smoking, and poor to fair health). Exclusion criteria were calcium supplementation > 500 mg/d, history of kidney or bladder stones, renal failure, hypercalcemia, cognitive impairment, or life expectancy < 6 months.
Intervention: Information leaflet alone (n = 1993) or 6-month supply of calcium, 1000 mg and cholecalciferol (vitamin D) 800 IU daily, taken as 2 tablets (Calcichew D, Forte, Hampshire, UK); lifestyle advice on how to reduce fracture risk; and an information leaflet on prevention of falls and calcium and vitamin D intake (n = 1321).
Outcomes: Any fracture (excluding ribs, digits, face, and skull). Secondary outcomes were hip fracture, quality of life (12-item Short Form Health Survey), death, hospital admissions and doctor visits, falls, and fear of falling. The study had 80% power to detect a 34% reduction in fracture.
Patient follow-up: 140 patients were excluded directly after randomization. 3314 patients (96%) were included in the intention-to-treat analysis.
During follow-up, 149 fractures were reported. Calcium and vitamin D supplementation did not reduce fractures (Table). Groups did not differ for quality of life, death, hospital admissions and doctor visits, and falls. The adjusted odds ratio for falling was 0.99 (95% CI 0.8 to 1.20) at 6 months and 0.93 (CI 0.79 to 1.20) at 12 months.
Supplementation with calcium and vitamin D for 2 years did not reduce the risk for fracture in at-risk community-dwelling older women.
Sources of funding: Northern and Yorkshire NHS Research and Development; Healthy Ageing Programme; Shire; Nycomed.
For correspondence: Dr. D.J. Torgerson, University of York, York, England, UK. E-mail email@example.com.
Table. Calcium and vitamin D supplementation vs no supplementation in older women at risk for fracture at median 25 months†
|Outcomes||Supplementation||No supplementation||RRR (CI)||NNT|
|Any fracture||4.4%||4.6%||3.8% (−32 to 30)||Not significant|
|Hip fracture||0.6%||0.9%||29% (−60 to 69)||Not significant|
†Abbreviations defined in Glossary; RRR, NNT, and CI calculated from data in article.
The review by Bischoff-Ferrari and colleagues, the study by Porthouse and colleagues, and the RECORD trial examined calcium and vitamin D supplementation for the prevention of fractures in older persons. The systematic review by Bischoff-Ferrari and coworkers found that high-dose vitamin D (700 to 800 IU/d) combined with calcium (500 to 1200 mg/d) reduced the risk for hip fractures by 26% (CI 12 to 39) and all nonvertebral fractures by 23% (CI 13 to 32). However, the RECORD and Porthouse studies (which were not included in the Bischoff-Ferrari review) reported no benefit of high-dose vitamin D and calcium for either secondary prevention of fractures or prevention of fractures in high-risk patients of whom over half had previous fractures. Could differences in patient populations, study power, or adherence to study drugs explain these seemingly discordant results?
The effect of vitamin D with or without calcium on fracture prevention may vary in different populations. Frail, elderly persons and nursing home patients are at greater risk for falls and fractures than community-dwelling elderly persons. This difference may in part be explained by vitamin D deficiency in persons who are often sunlight-deprived. Many of the patients in the Bischoff-Ferrari meta-analysis were nursing-home residents. A Cochrane review that included 4 recent studies (including the RECORD and Porthouse studies) found that vitamin D alone did not reduce fractures (1). However, when vitamin D was given in combination with calcium, reductions occurred in hip and nonvertebral fractures but not in vertebral fractures. Subgroup analysis suggested that this effect was restricted to elderly patients living in institutions, with a reduction in fractures of 13% (CI 5 to 28). In both the RECORD and Porthouse studies, patients were community-dwelling.
In the Porthouse and RECORD studies, power may not have been sufficient to show a clinically important difference, especially between the vitamin D plus calcium and placebo groups. The RECORD trial was designed to have 80% power to detect an absolute difference in fracture rates of 3% between treatment groups. The intervention groups were formed by collapsing the 2 groups that received the specific intervention (calcium or vitamin D), and the control groups were formed from the 2 groups that did not receive the intervention. The groups that received calcium with vitamin D only or placebo were smaller and had only about 62% power to detect a 3% difference in fracture rate between these 2 groups. In the study by Porthouse and colleagues, the authors could not exclude a reduction in risk < 30% for fractures with vitamin D plus calcium. Meta-analyses in a Cochrane study (1) and the study by Bischoff-Ferrari and colleagues both found reductions in risk for fractures < 30%.
Adherence to therapy and consequent vitamin D levels may have varied in these trials, resulting in differences in biological effects. A meta-regression analysis in Bischoff-Ferrari showed a greater reduction in hip and nonvertebral fractures with higher serum levels of 25-hydroxyvitamin D. 2 hip fracture studies that were included in the Bischoff-Ferrari meta-analysis (Decalyos II 2 and Decalyos I 3) reported exceptionally high rates of compliance with treatment and placebo (95% in Decalyos II and 83% in Decalyos I). In contrast, compliance rates were 60% in the RECORD trial, and 56.6% in the study by Porthouse and colleagues. For a subset of patients in the RECORD and Decalyos I studies, baseline 25-hydroxyvitamin D levels were similar (15.2 ng/mL and 16 ng/mL, respectively). However, after 1 year of treatment, the mean 25-hydroxyvitamin D levels in the Decalyos I treatment group increased to 42 ng/mL (3), while levels in the RECORD study only increased to 24.8 ng/mL.
The review by Bischoff-Ferrari and colleagues and the Porthouse and RECORD studies suggest that calcium plus high-dose vitamin D is effective for the prevention of hip and nonvertebral fractures in older persons, particularly those in institutions. It is important to note that in the secondary prevention trials, which showed the effectiveness of bisphosphonates, calcium and vitamin D were given to all participants (4-6). For patients with a previous low-impact fracture, prevention should include a bisphosphonate in addition to calcium and vitamin D.
Michael Bogaisky, MD
Rosanne M. Leipzig, MD, PhD
Mount Sinai Medical Center
New York, New York, USA
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