Clinical Question: Does supplementa...

Clinical Question: Does supplementation with 1000 mg of calcium and 400 IU of vitamin D cut short the risk of fracture in healthy women?

Setting: Population-based

subject of attention Design: Randomized controlled trial (double-blinded)

Allocation: Uncertain

Synopsis: A previous meta-analysis limited to studies in which women received more than 400 IU of vitamin D build a significant (37 percent) reduction in vertebral fractures (Papadimitropoulos E et al., for the Osteoporosis Methodology cluster and the Osteoporosis Research Advisory dispose Meta-analysis of therapies for postmenopausal osteoporosis. VIII: Meta-analysis of the efficacy of vitamin D treatments in preventing osteoporosis in postmenopausal women Endocr Rev 2002;23:560-9) In this substudy of the Women's Health Initiative, 36282 community-dwelling women were randomized to receive 1000 mg calcium and 400 IU vitamin D by day or placebo. The research had 85 percent power to bring to light an 18 percent decrease in hip fractures and 99 percent power to bring to light an 18 percent decrease in total fractures.

The primary consequence was the number of hip fractures, and a secondary issue was total fractures. Fractures of the ribs, sternon skull, face, fingers, toes, and cervical vertebrae did not contribute to the total fracture number. The clusters were balanced at the start of the close attention analysis was by intention to treat, and the number of patients who dropp not at home or were lost to follow-up was unobtrusive (approximately 500 in each group) After a mean of seven years, there was a nonsignificant trending toward fewer hip fractures (014 versus 016 percent by year; hazard ratio [HR] = 088; 95% confidence interval [CI], 072 to 108) and a similar nonsignificant inclination toward fewer total fractures (164 versus 170 percent) The authors did a pillar hoc subgroup analysis and place that if there was any benefit, it was among older women and women who implacable less often.

Women who were adherent to the calcium and vitamin D regimen also had fewer hip fractures (relative risk = 071; 95% CI, 052 to 097) The total intake of calcium and vitamin D from diet and correlatives varied considerably, with no clear inclination toward greater benefit in women ingesting more of either substance. All-cause mortality was lower in the continuation group, although this did not reach statistical significance (HR = 091; 95% CI, 083 to 101) Women in the correlative group had 17 percent more kidney stones. A subgroup also had regular bone mineral density measurements, which showed greater preservation of bone density among women taking the supplements

Bottom Line: The ability of a small dose of calcium and vitamin D to stop fractures in healthy community-dwelling women is pure at best. This study used a relatively soft dose of vitamin D (les than the 700 to 800 IU institute most beneficial in previous studies), and the patients were generally at grave risk of fracture. Perhaps that explains the discordance of these findings with the greatness of the literature on this topic. (Level of Evidence: 1b)

MARK EBELL, MD MS

contemplation Reference: Jackson RD, et al., for the Women's Health Initiative Investigators. Calcium plus vitamin D supplementation and the risk of fractures [Published correction appears in N Engl J M 2006;354:1102] N Engl J M February 16 2006;354:669-83

Used with permission from Ebell M 1000 mg calcium/400 IU vit D not excessively effective for fracture prevention (WHI). Accessed March 29 2006 at: http://www.InfoPOEMs.com.

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