Bone Mass Development from Childhood into Young Adulthood in Patients with Childhood-onset Inflammatory Bowel Disease

Background: Children who have inflammatory bowel disease (IBD) have increased risk of low bone mineral density (BMD). There is a scarcity of information on BMD development through puberty and into young adulthood in patients with childhood-onset IBD. Methods: We conducted a prospective longitudinal study of BMD in patients with childhood-onset IBD. In total, 74 children with IBD were followed into young adulthood, with a mean follow-up of 8.4 years. The BMD was assessed longitudinally using dual-energy X-ray absorptiometry of the lumbar spine, total hip and whole body, and related to anthropometric measures. Results: Young adult male patients with IBD had lower mean BMD Z-scores for the lumbar spine at 20.8 (+/- 1.1 SD) and total hip at -0.5 (+/- 0.9 SD), as compared to standard references. In young female patients, the BMD Z-scores were within the normal range at all 3 measured sites as compared to the standard references. There were no significant differences in the BMD Z-scores between patients with Crohn's disease and patients with ulcerative colitis. The female and male patients showed significantly improved mean lumbar spine BMD Z-scores during follow-up into young adulthood, indicating that bone accumulation in the lumbar spine continues beyond the expected age for achieving peak bone mass. Conclusions: Male patients with childhood-onset IBD seem to have an increased risk of compromised BMD in young adulthood. Both female and male patients with IBD seem to increase their BMD beyond the age for expected peak bone mass.