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Spencer L1, McKenna L1, Fary R1, Ho R1, Briffa K1
1Curtin University, School of Physiotherapy and Exercise Science, Perth, Australia
Background: Upper back pain often reported by post-menopausal women seems to be more common among those who have large breasts. It is plausible that large breasts may lead to habitually flexed posture and a greater thoracic kyphosis placing a load on the thoracic spine that may increase the risk of vertebral fracture.
Purpose: To examine breast size as an independent predictor of thoracic vertebral fracture in postmenopausal women.
Methods: This was a cross-sectional study of postmenopausal women. Objective measurements were collected on: thoracic vertebral fractures (defined as ≥20% loss in vertebral body height on lateral radiograph); breast size (bra size converted to breast form score); bone mineral density (T-score of left neck of femur using Dual x-ray absorptiometry, DXA); upper back extensor muscle endurance (Isometric chest raise test); body composition (DXA) and thoracic kyphosis (radiograph). Data were analysed using binary logistic regression analysis with vertebral fracture (yes/no) as the dependent variable. Initially each physical characteristic was entered into univariable models. Those variables with a significant association with fracture were then entered into a multivariate model.
Results: 117 postmenopausal women, 17 (15%) with ≥1 thoracic vertebral fracture participated in the study. Women with fracture had a larger breast size (Mean difference (MD): 1.38 sizes, 95%CI: 0.92-2.67 sizes), lower upper back muscle endurance (MD: 38.60s, 95%CI: 14.30-62.90s) and greater thoracic kyphosis (MD: 7.25° 95%CI: 1.7-12.78°), compared to those without fracture. Characteristics that were associated with increased odds for vertebral fracture were an increased breast size (OR: 1.26, 95%CI: 1.01-1.57) and thoracic kyphosis (OR: 1.07, 95%CI: 1.01-1.13). Although greater upper back extensor muscle endurance was associated with a significant decrease in odds for vertebral fracture (OR: 0.99, 95%CI: 0.98-1.00) in univariable models it was not significant in the final multivariate model. The final multivariate model, containing breast size and thoracic kyphosis, was significant (p=.004) and explained 16% of the variance in vertebral fracture
Conclusion(s): Breast size and thoracic kyphosis are associated with thoracic vertebral fracture in postmenopausal women. Prospective studies to determine the temporal relationship between breast size, kyphosis and fracture risk is required to determine causality.
Implications: Thoracic vertebral fractures could be considered a burden of large breasts. This study potentially provides a rationale for the future funding of reduction mammoplasty surgery as a medical rather than cosmetic procedure.
Keywords: Thoracic vertebral fracture, Breast size, Thoracic kyphosis
Funding acknowledgements: Primary researcher (LS) was supported by an Australian Government Research Training Program Scholarship and Curtin University Research Scholarship.
Purpose: To examine breast size as an independent predictor of thoracic vertebral fracture in postmenopausal women.
Methods: This was a cross-sectional study of postmenopausal women. Objective measurements were collected on: thoracic vertebral fractures (defined as ≥20% loss in vertebral body height on lateral radiograph); breast size (bra size converted to breast form score); bone mineral density (T-score of left neck of femur using Dual x-ray absorptiometry, DXA); upper back extensor muscle endurance (Isometric chest raise test); body composition (DXA) and thoracic kyphosis (radiograph). Data were analysed using binary logistic regression analysis with vertebral fracture (yes/no) as the dependent variable. Initially each physical characteristic was entered into univariable models. Those variables with a significant association with fracture were then entered into a multivariate model.
Results: 117 postmenopausal women, 17 (15%) with ≥1 thoracic vertebral fracture participated in the study. Women with fracture had a larger breast size (Mean difference (MD): 1.38 sizes, 95%CI: 0.92-2.67 sizes), lower upper back muscle endurance (MD: 38.60s, 95%CI: 14.30-62.90s) and greater thoracic kyphosis (MD: 7.25° 95%CI: 1.7-12.78°), compared to those without fracture. Characteristics that were associated with increased odds for vertebral fracture were an increased breast size (OR: 1.26, 95%CI: 1.01-1.57) and thoracic kyphosis (OR: 1.07, 95%CI: 1.01-1.13). Although greater upper back extensor muscle endurance was associated with a significant decrease in odds for vertebral fracture (OR: 0.99, 95%CI: 0.98-1.00) in univariable models it was not significant in the final multivariate model. The final multivariate model, containing breast size and thoracic kyphosis, was significant (p=.004) and explained 16% of the variance in vertebral fracture
Conclusion(s): Breast size and thoracic kyphosis are associated with thoracic vertebral fracture in postmenopausal women. Prospective studies to determine the temporal relationship between breast size, kyphosis and fracture risk is required to determine causality.
Implications: Thoracic vertebral fractures could be considered a burden of large breasts. This study potentially provides a rationale for the future funding of reduction mammoplasty surgery as a medical rather than cosmetic procedure.
Keywords: Thoracic vertebral fracture, Breast size, Thoracic kyphosis
Funding acknowledgements: Primary researcher (LS) was supported by an Australian Government Research Training Program Scholarship and Curtin University Research Scholarship.
Topic: Musculoskeletal: spine; Older people
Ethics approval required: Yes
Institution: Curtin University
Ethics committee: Human Research Ethics Committee
Ethics number: RDHS-267-15
All authors, affiliations and abstracts have been published as submitted.
