Differential Impact of Type 1 Diabetes on Bone Outcomes in Children.

OBJECTIVES: Type 1 diabetes (T1D) is a recognized risk factor for skeletal fragility in adults, but its impact on bone microstructure in children remains incompletely characterized. In particular, data on trabecular bone quality remain scarce. This study aimed to evaluate skeletal parameters in this group of children and examine their associations with clinical variables. METHODS: This retrospective cross-sectional study evaluated children with T1D at the Hong Kong Children's Hospital from June 2023 to December 2024. Skeletal parameters, including trabecular bone score (TBS), bone health index (BHI), bone mineral density (BMD) by dual-energy x-ray absorptiometry, and serum vitamin D and HbA1c levels, were evaluated alongside fracture history. A parent-reported questionnaire measured participation in physical activity. Correlations between bone parameters and clinical variables were analyzed. RESULTS: Sixty-eight children with T1D (male 42.6%, mean 12.7 ± 3.7 years, 44.1% prepubertal, mean HbA1c 7.3%) were included. A substantial proportion of children (19.6%) had low cortical bone density as reflected by BHI Z-score ≤ -2, whereas deficits in trabecular bone (TBS Z-score ≤ -2) were less common (4.8 %). Regression analysis confirmed that higher lean mass was associated with higher total body less head (TBLH), lumbar spine (LS) and TBS Z-scores (β=0.0001, p < 0.05), while disease duration had a negative association with these measurements (β=-0.1413; β =-0.1335, β=-0.2270, p < 0.05). CONCLUSION: In this cohort of children with T1D, a pattern of skeletal involvement was observed, characterized by a high prevalence of low BHI Z-scores and a relatively low prevalence of low TBS Z-scores. This may suggest differential involvement of cortical bone with relative preservation of trabecular microarchitecture. Whether these structural differences translate into fracture risk remains unknown. Longitudinal studies are needed to elucidate the evolution of bone alterations over time and to identify determinants underlying skeletal vulnerability in childhood-onset diabetes. Higher lean mass was associated with higher bone mass and microarchitectural indices, whereas longer disease duration may have a negative association with these parameters. These findings highlight modifiable and disease-related factors that may influence bone health, warranting confirmation in larger controlled studies.