BACKGROUND: Low bone density and fractures are common in patients with inflammatory bowel disease (IBD).OBJECTIVE: To determine whether the bisphosphonate risedronate and calcium are safe and effective in preserving bone mass compared to calcium alone in IBD patients with low bone mass.PATIENTS: Sixty-one ambulatory patients with Crohn's disease (n = 31) or ulcerative colitis (n = 30) and low bone density.METHODS: Using a double-blind placebo-controlled trial format, patients were randomized to 12 months of therapy with risedronate 5 mg or placebo. All received a 600 mg calcium supplement. Bone density using dual energy X-ray absorptiometry was performed at baseline and at 12 months. Disease activity, use of corticosteroid, and adverse events were noted.RESULTS: Forty-eight patients completed the trial. Compared to the placebo group risedronate resulted in a 2.0% (95%CI, 0.02-3.97) and 1.9% (95%CI, 0.21-3.62) improvement in bone density at the spine and hip, respectively. IBD diagnosis, gender, therapy, and disease status had no effect on the results. There were no significant differences in the adverse events.CONCLUSIONS: Risedronate improved bone density at the spine and hip in patients with either Crohn's disease or ulcerative colitis and low bone mass. These data suggest that risedronate is a safe and effective therapy to improve bone mass in these patients.