Thoracic kyphosis and rate of incident vertebral fractures: the Fracture Intervention Trial

• Published in: Osteoporosis international 2016-03, Vol.27 (3), p.899-903
• Main Authors: Katzman, W. B., Vittinghoff, E., Kado, D. M., Lane, N. E., Ensrud, K. E., Shipp, K.
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Analysis; Biomechanics; Bone Density - physiology; Clinical trials; Endocrinology; Female; Femur Neck - physiopathology; Fractures; Humans; Incidence; Kyphosis - complications; Kyphosis - epidemiology; Kyphosis - pathology; Kyphosis - physiopathology; Lumbar Vertebrae - injuries; Medicine; Medicine & Public Health; Middle Aged; Original Article; Orthopedics; Osteoporosis, Postmenopausal - complications; Osteoporosis, Postmenopausal - epidemiology; Osteoporosis, Postmenopausal - physiopathology; Osteoporotic Fractures - epidemiology; Osteoporotic Fractures - etiology; Osteoporotic Fractures - physiopathology; Prevalence; Rheumatology; Risk Factors; Spinal Fractures - epidemiology; Spinal Fractures - etiology; Spinal Fractures - physiopathology; Spine; Thoracic Vertebrae - injuries; United States - epidemiology
• ISSN: 0937-941X; 1433-2965
• DOI: 10.1007/s00198-015-3478-2

Summary Biomechanical analyses support the theory that thoracic spine hyperkyphosis may increase risk of new vertebral fractures. While greater kyphosis was associated with an increased rate of incident vertebral fractures, our analysis does not show an independent association of kyphosis on incident fracture, after adjustment for prevalent vertebral fracture. Excessive kyphosis may still be a clinical marker for prevalent vertebral fracture. Introduction Biomechanical analyses suggest hyperkyphosis may increase risk of incident vertebral fracture by increasing the load on vertebral bodies during daily activities. We propose to assess the association of kyphosis with incident radiographic vertebral fracture. Methods We used data from the Fracture Intervention Trial among 3038 women 55–81 years of age with low bone mineral density (BMD). Baseline kyphosis angle was measured using a Debrunner kyphometer. Vertebral fractures were assessed at baseline and follow-up from lateral radiographs of the thoracic and lumbar spine. We used Poisson models to estimate the independent association of kyphosis with incident fracture, controlling for age and femoral neck BMD. Results Mean baseline kyphosis was 48° (SD = 12) (range 7–83). At baseline, 962 (32 %) participants had a prevalent fracture. There were 221 incident fractures over a median of 4 years. At baseline, prevalent fracture was associated with 3.7° greater average kyphosis (95 % CI 2.8–4.6, p