Vitamin D Supplementation Requires Additional Calcium to Reduce Hip Fractures


[center]NEW YORK (Reuters Health) May 18 - The risk of
hip fracture appears to be reduced with oral vitamin D supplementation
only when it is accompanied by additional calcium, according to a
report in the April issue of The Journal of Clinical Endocrinology
& Metabolism.

"Supplementation should be targeted to individuals with
insufficiencies," Dr. Steven Boonen from Katholieke Universiteit
Leuven, Belgium told Reuters Health. "And that is why supplementation
should focus on individuals with documented calcium (<1200 mg/d) and
vitamin D (<50 nmol/L) insufficiency, individuals most likely to be
calcium and vitamin D insufficient (subjects older than 75, home
bound, or institutionalized), and patients with documented osteoporosis
on anabolic or antiresorptive therapy."

Dr. Boonen and associates performed an adjusted indirect comparison of
two pooled-risk estimates for hip fracture: one from a meta-analysis of
vitamin D trials and one from a meta-analysis of vitamin D plus
calcium trials, both compared with placebo or no treatment.

The pooled relative risk for hip fracture from the vitamin D only
trials was a statistically nonsignificant 1.10, the authors report. In
contrast, the pooled relative risk from vitamin D plus calcium trials
was a statistically significant 0.82, the report indicates.

Comparing the two meta-analyses gave a significant adjusted relative
risk of 0.75 in favor of vitamin D with additional calcium, the
investigators say, "suggesting that the combination reduces the risk of
hip fracture by 25% compared with vitamin D alone."

"A negative calcium balance is driving bone loss with aging, and in
most individuals this negative calcium balance is due to the
combination of inadequate calcium intake and suboptimal vitamin D
status," Dr. Boonen said. "That is why, in most individuals, a
combination of calcium and vitamin D is required to restore calcium
balance and reduce fracture risk."

"Current evidence indicates that you need at least 800 IU of vitamin D
to reduce fracture risk (and that you need additional calcium
supplements), but what we don't know is whether 800 IU of vitamin D is
the optimal dose for musculoskeletal health," Dr. Boonen added. "Future
research should focus on this question."

J Clin Endocrinol Metab 2007;92:1415-1423.

Source: http://www.medscape.com/viewarticle/556725?src=mp