title: Prognostic Value of Bone Mineral Density on Curve Progression: A Longitudinal Cohort Study of 513 Girls with Adolescent Idiopathic Scoliosis.
abstract: 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.
authors.affiliation: Department of Orthopaedics and Traumatology, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.|JC School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Benjamin Hon Kei
authors.initials: BHK
authors.lastname: Yip
authors.affiliation: Department of Orthopaedics and Traumatology, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.|Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, Hong Kong.|Bone Quality and Health Centre, Department of Orthopaedics and Traumatology, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.|SH Ho Scoliosis Research Laboratory, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Fiona Wai Ping
authors.initials: FWP
authors.lastname: Yu
authors.affiliation: Department of Orthopaedics and Traumatology, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.|Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, Hong Kong.|Department of Orthopedic Surgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Orthopaedics and Traumatology, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.|Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, Hong Kong.|Bone Quality and Health Centre, Department of Orthopaedics and Traumatology, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.|SH Ho Scoliosis Research Laboratory, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Vivian Wing Yin
authors.initials: VWY
authors.lastname: Hung
authors.affiliation: Department of Orthopaedics and Traumatology, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.|Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, Hong Kong.|Bone Quality and Health Centre, Department of Orthopaedics and Traumatology, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.|SH Ho Scoliosis Research Laboratory, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Tsz Ping
authors.initials: TP
authors.lastname: Lam
authors.affiliation: Department of Orthopaedics and Traumatology, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Bobby Kin Wah
authors.initials: BKW
authors.lastname: Ng
authors.affiliation: Department of Orthopaedics and Traumatology, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.|Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, Hong Kong.|Spine Surgery, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhu
authors.affiliation: Department of Orthopaedics and Traumatology, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.|Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, Hong Kong.|Bone Quality and Health Centre, Department of Orthopaedics and Traumatology, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.|SH Ho Scoliosis Research Laboratory, Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Jack Chun Yiu
authors.initials: JCY
authors.lastname: Cheng
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D015519:Bone Density / Q000502:physiology*; D001851:Bone Diseases, Metabolic / Q000150:complications; D018450:Disease Progression; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D011379:Prognosis; D016016:Proportional Hazards Models; D012307:Risk Factors; D012600:Scoliosis / Q000150:complications / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D014057:Tomography, X-Ray Computed