Longitudinal changes in bone mineral density in children with inflammatory bowel diseases.

Aim: Children with inflammatory bowel disease (IBD) are prone to low bone mineral density (BMD). Our aim was to assess longitudinal changes in BMD in this population.

Methods: A retrospective longitudinal study of children with IBD, treated at two tertiary centres in Israel, who underwent two BMD measurements by dual-energy X-ray absorptiometry (DXA). Changes in lumbar spine BMD (∆L1-4 z-scores) were examined for correlations with clinical characteristics.

Results: The cohort included 41 patients (age at diagnosis 12.1 ± 3.5 years, 23 females).The mean interval between the scans was 3.4 ± 2.0 years. There was a trend towards improvement in L1-4 z-scores (-1.64 ± 1.02 vs -1.45 ± 0.83, P = .12). ∆L1-4 z-scores correlated positively with ∆weight-standard deviation scores (SDS), ∆height-SDS and ∆BMI-SDS, and with age at the second scan (R = .55, P < .01; R = .42, P < .01; R = .42, P = .01; R = .35, P = .02, respectively); and negatively with L1-4 z-scores at the first scan (R = -.63, P < .01). Stepwise linear regression analysis identified the first scan L1-4 z-scores and ∆weight-SDS as independent predictors of ∆L1-4 z-scores. An L1-4 z-score ≤-2 at the first DXA scan was associated with significant improvement at the second scan.

Conclusion: Improvement in BMD was more pronounced in children who gained weight or whose BMD was low at the first scan.