Compromised peak bone mass in patients with inflammatory bowel disease--a prospective study.

OBJECTIVE: To evaluate peak bone mass attainment in children and adolescents with inflammatory bowel disease and to identify risk factors for suboptimal bone mass attainment.

STUDY DESIGN: We conducted a prospective follow-up study of 47 children and adolescents (24 males) with ulcerative colitis (n = 30) or Crohn's disease (n = 17). They were assessed for lumbar spine areal bone mineral density (aBMD) and for height-adjusted whole body less head bone mineral content (BMC); the values were corrected for bone age.

RESULTS: Altogether, 73% of the patients had completed pubertal development after the median follow-up time of over 5 years. Despite clinical inactivity of the disease in 70% of the patients at the follow-up visit, BMD or BMC Z-scores improved in none of the measurement sites. Lumbar spine aBMD Z-scores (mean difference [95% CI], -0.47 [-0.92 to -0.03]; P = .04) and whole body less head BMC height- and bone age-adjusted Z-scores (-0.52 [-1.01 to -0.02]; P = .04) decreased in patients who were pubertal at baseline and completed their pubertal development during the follow-up. Postpubertal patients had lower aBMD and BMC Z-scores in comparison with prepubertal and pubertal patients. Low lumbar spine aBMD (Z-score < -1.0) was associated with completed pubertal development, underweight, and greater lifetime cumulative weight-adjusted prednisolone dose. Vertebral fractures were detected in 3 patients (6%). One-fourth of the patients had insufficient serum 25-hydroxyvitamin D concentrations (<50 nmol/L).

CONCLUSIONS: The longitudinal follow-up over the pubertal years shows that inflammatory bowel disease poses a significant threat for bone health. The suboptimal peak bone mass attainment may have life-long consequences.