Calcium plus vitamin D supplementation and the risk of fractures.
- R. Jackson
- A. LaCroix
- M. Gass
- R. Wallace
- J. Robbins
- Cora E. Lewis
- T. Bassford
- S. Beresford
- H. Black
- P. Blanchette
- D. Bonds
- R. Brunner
- R. Brzyski
- B. Caan
- J. Cauley
- R. Chlebowski
- S. Cummings
- Iris A. Granek
- J. Hays
- G. Heiss
- S. Hendrix
- B. Howard
- J. Hsia
- F. Hubbell
- K. Johnson
- H. Judd
- J. Kotchen
- L. Kuller
- R. Langer
- N. Lasser
- M. Limacher
- S. Ludlam
- J. Manson
- K. Margolis
- J. McGowan
- J. Ockene
- M. O'sullivan
- L. Phillips
- R. Prentice
- G. Sarto
- M. Stefanick
- L. V. Van Horn
- J. Wactawski‐Wende
- E. Whitlock
- G. Anderson
- A. Assaf
- D. Barad
What this study found
Calcium plus vitamin D did not significantly reduce hip fracture or total fractures, although it produced a small improvement in hip bone density. Hip fracture occurred in 175 women in the calcium plus vitamin D group versus 199 in placebo (hazard ratio 0.88, 95% CI 0.72-1.08), and total fractures occurred in 2102 versus 2158 (hazard ratio 0.96, 95% CI 0.91-1.02). Hip bone density was 1.06 percent higher in the calcium plus vitamin D group (P<0.01), and the adherence-adjusted hip fracture hazard ratio was 0.71 (0.52-0.97). The regimen increased renal calculi risk (hazard ratio 1.17, 95% CI…
- Study & population
- Randomized, placebo-controlled trial in healthy postmenopausal women aged 50 to 79 years enrolled at 40 Women's Health Initiative clinical centers in the United States.
- Intervention
- The active regimen was oral calcium carbonate plus vitamin D3: each tablet contained 500 mg elemental calcium and 200 IU vitamin D3, taken as two tablets per day in divided doses with meals.
- Key limitation
- Fracture outcomes were not significantly improved in the intention-to-treat analysis despite a bone density benefit, and adherence influenced the apparent hip-fracture reduction.
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Open PDFOriginal abstract
BACKGROUND The efficacy of calcium with vitamin D supplementation for preventing hip and other fractures in healthy postmenopausal women remains equivocal. METHODS We recruited 36,282 postmenopausal women, 50 to 79 years of age, who were already enrolled in a Women's Health Initiative (WHI) clinical trial. We randomly assigned participants to receive 1000 mg of elemental [corrected] calcium as calcium carbonate with 400 IU of vitamin D3 daily or placebo. Fractures were ascertained for an average follow-up period of 7.0 years. Bone density was measured at three WHI centers. RESULTS Hip bone density was 1.06 percent higher in the calcium plus vitamin D group than in the placebo group (P<0.01). Intention-to-treat analysis indicated that participants receiving calcium plus vitamin D supplementation had a hazard ratio of 0.88 for hip fracture (95 percent confidence interval, 0.72 to 1.08), 0.90 for clinical spine fracture (0.74 to 1.10), and 0.96 for total fractures (0.91 to 1.02). The risk of renal calculi increased with calcium plus vitamin D (hazard ratio, 1.17; 95 percent confidence interval, 1.02 to 1.34). Censoring data from women when they ceased to adhere to the study medication reduced the hazard ratio for hip fracture to 0.71 (95 percent confidence interval, 0.52 to 0.97). Effects did not vary significantly according to prerandomization serum vitamin D levels. CONCLUSIONS Among healthy postmenopausal women, calcium with vitamin D supplementation resulted in a small but significant improvement in hip bone density, did not significantly reduce hip fracture, and increased the risk of kidney stones. (ClinicalTrials.gov number, NCT00000611.).