Bone density in healthy men after cessation of calcium supplements: 20-month follow-up of a randomized controlled trial.

Abstract

Bone density has been followed up for 20 months following completion of a trial which compared calcium 1,200 mg/day with placebo, in normal older men. Following cessation of calcium supplements, there is a small residual benefit in total body bone density, but not at the hip or spine. Calcium supplements, or supplements of calcium-rich foods, have a positive effect on bone mineral density (BMD). However, it is uncertain whether there are any residual benefits of calcium on BMD following cessation of supplementation. In a previously published study, 323 healthy men were randomized to receive elemental calcium 600 mg/day (n = 108), calcium 1,200 mg/day (n = 108), or placebo (n = 107) over 2 years. Consenting men from the placebo and calcium 1,200 mg/day groups (85 and 87, respectively) were followed over the next 1-2 years (mean 20 months), off trial medication. In the core trial, BMD increased at all sites by 1.0-1.5% at 2 years in the group receiving calcium 1,200 mg/day, compared to the group receiving placebo. In post-trial follow-up, the calcium group has some residual benefit at the total body (0.41% above placebo; P = 0.04) but there was no significant between-group differences at other sites. Following cessation of calcium supplements in healthy men, there is a small residual benefit in total body BMD, but not at the hip or spine. This is unlikely to confer a clinically significant dividend in terms of ongoing fracture prevention.