NEW YORK (Reuters Health) - In elderly women, adding vitamin D to regular calcium supplements produces long-term improvements in hip bone density, researchers report.

To evaluate the relative benefits of calcium with or without vitamin D on bone health, Dr. Richard Prince, at the University of Western Australia, Perth, assigned 120 women to take 1200 milligrams of calcium daily along with an inactive placebo pill or a vitamin D tablet, or two placebo tablets.

The women were between 70 and 80 years old. After one year, bone mineral density at the hip was preserved in the calcium group and the calcium+vitamin D group, but not in the double-placebo "control" group.

However, at three and five years, only the group that got calcium plus vitamin D group maintained hip bone density, the investigators report in the Journal of Clinical Endocrinology and Metabolism.