Assessment of Bone Mass and Fracture Risk Using Trabecular Bone Score in Children with Autoimmune Gastrointestinal...

Background/Objectives: Children with autoimmune gastrointestinal diseases are at increased risk of impaired bone health due to chronic inflammation, nutritional deficiencies, growth disturbances, and treatment-related factors. While dual-energy X-ray absorptiometry (DXA) is the standard method for assessing bone mineral density (BMD), it provides limited information on bone microarchitecture. The trabecular bone score (TBS), derived from lumbar spine DXA images, has emerged as a complementary marker of bone quality. This study aimed to evaluate bone mass and TBS in children with autoimmune gastrointestinal diseases and to assess the clinical utility of TBS in comparison with children with a history of fractures and healthy controls. Methods: This study included 152 children aged 5-18 years: 45 with autoimmune gastrointestinal diseases (Crohn's disease, ulcerative colitis, or celiac disease), 37 with a history of fractures, and 70 healthy controls. Anthropometric measurements, serum 25-hydroxyvitamin D [25(OH)D] concentrations, DXA-derived parameters, and TBS values were analyzed. Bone mineral density was assessed at the lumbar spine and total body less head (TBLH), with additional adjustment for height-for-age Z-score (HAZ). TBS values were expressed as sex- and pubertal stage-adjusted Z-scores. Results: Low bone mass (aBMD_{for age} Z-score ≤ -2) was observed in 30.3% of participants at TBLH and 11.1% at the lumbar spine, whereas a TBS Z-score ≤ -2 was identified in 5.2% of children. No significant differences in TBS or TBS Z-scores were found among the study groups. In multivariable analysis, fracture history was independently associated with lower absolute TBS, whereas no independent predictors of TBS Z-score were identified. Children with fractures had significantly lower HAZ-adjusted lumbar spine aBMD Z-scores than children with autoimmune gastrointestinal diseases and controls. TBS Z-scores correlated positively with age-adjusted and HAZ-adjusted aBMD values but showed no association with BMI or serum 25(OH)D concentrations. Conclusions: In this cross-sectional study, TBS did not distinguish children with autoimmune gastrointestinal diseases from those with fractures or healthy controls in the unadjusted analyses. Although TBS was associated with selected DXA-derived measures of bone mineral density and fracture history was independently associated with lower absolute TBS after multivariable adjustment, no independent predictors of TBS Z-score were identified. These findings suggest that the clinical role of TBS in the assessment of pediatric bone health remains to be established. Larger prospective studies are crucial to determine whether TBS provides clinically meaningful information complementary to conventional DXA for the assessment of skeletal health and fracture risk in children. Larger prospective studies are needed to clarify the clinical value of TBS for fracture risk assessment in pediatric autoimmune gastrointestinal diseases.