Factors affecting bone mineral density in children and adolescents with secondary osteoporosis

Purpose: This study aimed to investigate the clinical factors associated with bone mineral density (BMD) among children and adolescents with osteoporosis secondary to treatment for underlying clinical conditions. Methods: We retrospectively reviewed the medical records of patients aged 10-18 years and evaluated them for lumbar spine BMD (LSBMD) after treatment for underlying diseases, including hemato-oncologic, rheumatologic system, and inflammatory bowel diseases. LSBMD measured by dual-energy x-ray absorptiometry (DXA) performed from March 2019 to March 2021 was evaluated. We analyzed 117 patients who underwent initial DXA after treatment for underlying diseases. Results: Subjects in this study had multiple underlying diseases: hemato-oncologic (78.6%), rheumatologic (11.1%), and inflammatory bowel diseases (10.3%). There was no significant association between the z-score and bone metabolic markers (P>0.05). However, higher cumulative glucocorticoid (GC) dose significantly reduced LSBMD z-score (P=0.029). Moreover, the association between cumulative dose of GC and initial z-score of LSBMD was significant in logarithmic regression analysis (P=0.003, R-2=0.149). GC accumulation was a significant risk factor for vertebral fracture when the initial BMD was evaluated after treatment (P=0.043). Bone metabolic markers did not significantly influence the risk of vertebral fracture. Conclusion: Initial bone mass density of the lumbar spine evaluated after long-term GC use for underlying diseases is a predictor of further vertebral fractures.