‘Modest’ benefits of calcium, vitamin D supplementation on hip geometry
MedWire News: Calcium plus vitamin D (CaD) supplementation may reduce hip fracture risk by improving hip structural features at the femoral neck, a study among menopausal women has shown.
After 6 years taking a CaD supplement, bone mineral density (BMD) and the geometric parameters of cross-sectional area and section modulus increased "modestly" at the femoral neck, while buckling ratio decreased - indicating greater bone strength - say the researchers.
Previous studies have shown that CaD supplementation has a modest but significant effect on slowing the loss of femoral bone mass and reducing hip fracture risk in postmenopausal women.
Here, Rebecca Jackson (The Ohio State University, Columbus, USA) and colleagues applied hip structural analysis to dual-energy X-ray absorptiometry to explore the mechanical implications of CaD on bone at the femoral neck, intertrochanter, and shaft.
They studied 1970 postmenopausal women (mean age 62 years) enrolled in the Women's Health Initiative randomized controlled trial of CaD supplementation; 991 women received CaD while the remaining 979 received placebo.
When comparing the percent difference between baseline measurements and those taken at year 6, the researchers found that femoral neck BMD and cross-sectional area increased significantly, by approximately 1%, relative to placebo.
The team also observed a non-significant increase in section modulus, and a decrease in buckling ratio with CaD relative to placebo.
Similar trends were observed at both the intertrochanter and shaft regions but these did not reach significance.
Writing in the journal Calcified Tissue International the researchers conclude that: "CaD supplementation is associated with modest beneficial effects on hip structural features at the femoral narrow neck."
They add that their data "support a hypothesis that some of the benefit of CaD in reducing hip fracture risk may result from enhanced geometric properties that lead to improved bone strength."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Laura Dean