 This is an institutional, randomized, placebo-controlled, double-blind clinical trial to compare the efficacy of intranasally administered calcitonin plus oral supplements of age-appropriate doses of calcium and vitamin D with that of placebo nasal spray plus oral supplements of age-appropriate doses of calcium and vitamin D in maintaining or improving bone mineral density. Study subjects will be 8 to 22 year old patients with the diagnosis of inflammatory bowel disease ulcerative colitis and Crohns disease and low bone mineral density defined as DXA z score lower than -1.0 SD. Study end-point will be at 18 months after the continuous administration of nasal calcitonin or placebo and supplements as above. Bone mineral density will be measured by dual energy X-Ray absorptiometry DXA at the beginning of the study, and then at 9 and 18 months. The study subjects will be evaluated clinically and nutritionally at the beginning of the study, as well as every 3 months for the duration of the study. Laboratory values relevant to calcium homeostasis and bone turnover will be obtained every 3 months. 