THE EFFECT OF A SHORT-COURSE OF CALCIUM AND VITAMIN-D ON BONE TURNOVER IN OLDER WOMEN

Calcium and vitamin D (1200 mg/day + 800 IU) has been shown to reduce hip fracture incidence in older women living in long-term care facilit ies who had borderline roar vitamin D levels. We examined the effect o f a short course of calcium and vitamin D on biochemical markers of bo ne turnover in older community-living women. Twelve community-living w omen (mean age 75 years) in good general health, without diseases or a l? medications known to affect bone, were entered into the study, All women were treated with calcium citrate (1500 mg/day of elemental calc ium) and vitamin D-3 (1000 IU/day) (Ca + D) for G weeks, Biochemical m arkers of bone turnover were measured in serum and urine collected at baseline (two samples), 5 and ii weeks on Ca + D, and 5 and Ci weeks a fter termination of Ca + D. Markers of bone formation were osteocalcin , bone alkaline phosphatase and type I procollagen peptide. Markers of bone resorption were urinary hydroxyproline, free pyridinoline and de oxypyridinoline crosslinks, and N-telopeptides of type I collagen. Par athyroid hormone (PTH) and 25-hydroxyvitamin D were also measured al b aseline, Ci weeks on treatment and G weeks after termination of treatm ent. All markers of bone resorption decreased on Ca + D and returned t o baseline after termination of Ca + D (p<0.05). Markers of bone forma tion did not change with Ca + D treatment. PTH decreased on Ca + D and returned to baseline after treatment, and 25-hydroxyvitamin D increas ed with treatment and remained elevated G weeks after the end of treat ment. We conclude that Ca 3 D reduces bone resorption in older women, possibly by suppressing PTH levels.