Prognostic Value of Bone Mineral Density on Curve Progression: A Longitudinal Cohort Study of 513 Girls with Adolescent Idiopathic Scoliosis

• Published in: Scientific reports Vol. 6; no. 1; p. 39220
• Main Authors: YIP, Benjamin Hon Kei, YU, Fiona Wai Ping, WANG, Zhiwei, HUNG, Vivian Wing Yin, LAM, Tsz Ping, NG, Bobby Kin Wah, ZHU, Feng, CHENG, Jack Chun Yiu
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19.12.2016; Nature Publishing Group
• Subjects: 692/499; 692/53/2422; 692/699/1670/1669; Absorptiometry, Photon; Adolescent; Adolescents; Bone density; Bone Density - physiology; Bone Diseases, Metabolic - complications; Bone mineral density; Bone surgery; Cohort analysis; Computed tomography; Cortical bone; Disease Progression; Dual energy X-ray absorptiometry; Female; Health risk assessment; Humanities and Social Sciences; Humans; Longitudinal Studies; Menarche; multidisciplinary; Osteopenia; Prognosis; Proportional Hazards Models; Radius; Risk Factors; Science; Scoliosis; Scoliosis - complications; Scoliosis - diagnosis; Scoliosis - pathology; Scoliosis - surgery; Spine; Statistical analysis; Tomography, X-Ray Computed
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep39220

Osteopenia has been found to occur in about 30% of Adolescent Idiopathic Scoliosis (AIS) patients. This study aimed to investigate its prognostic value on the risk of curve progression to surgical threshold. Newly diagnosed AIS girls (N = 513) with Cobb angle 10°–40° were recruited with follow-up till maturity. Bilateral hips were assessed with dual-energy x-ray absorptiometry (DXA). Distal radius of a subgroup of 90 subjects was further assessed with high-resolution peripheral quantitative computed tomography (HR-pQCT). 55 patients progressed to surgical threshold or underwent spine surgery at the end of follow-up. Cox model with osteopenia status performed significantly better than the model without (p = 0.010). Osteopenic patients had significantly higher risk of surgery (HR2.25, p = 0.011), even after adjustment for menarche status, age and initial Cobb angle. The incremental predictive value of osteopenia was, however, not statistically significant. In the subgroup analysis, cortical bone density was identified as a better marker to improve the sensitivity of the prediction, but requires further larger study to validate this finding. These consistent results of bone density measured at different sites suggest a systemic effect, rather than local effect to the deformed spine, and support to the link of abnormal bone density to the etiopathogenesis in AIS patients.