title: High Cardiorespiratory Fitness Is Associated with Reduced Risk of Low Bone Density in Postmenopausal Women.
abstract: OBJECTIVE
  The goal of this study was to determine the association between cardiorespiratory fitness (CRF) and bone mineral density (BMD) of the femoral neck (FN) in postmenopausal women using existing Cooper Center Longitudinal Study data.
  
  
  METHODS
  A cohort of 1,720 predominantly healthy Caucasian women (57.1 ± 6.9 years) underwent preventive medical examinations that included CRF assessment by maximal Balke treadmill testing and measurement of BMD by dual-energy X-ray absorptiometry. CRF was estimated from total treadmill time and categorized into five categories of CRF (further defined as fitness category 1 = low fitness, 2-3 = moderate fitness, and 4-5 = high fitness). Logistic regression was used to characterize the association between CRF and BMD, adjusting for age, weight, and resistance activity level.
  
  
  RESULTS
  Overall, the mean body-mass index (BMI) for all subjects was 25.0 ± 4.5 kg/m2, although BMI was in the obese range in the low fitness group. The prevalence of osteoporosis (T-score ≤ -2.5 at the FN) was greater in the low fit group than moderate or high fit (5.8% vs. 3.0% or 3.9%, respectively); with a similar pattern seen for prevalence of osteopenia (T-score > -2.5 and ≤ -1.0 at the FN) (47.5% vs. 46.4% or 44.8%, respectively). Higher age and lower weight were associated with low BMD. Fully adjusted logistic regression models showed an inverse association between CRF and low BMD of the FN. For T-score ≤ -1.0, the primary outcome, the odds ratio (OR) was 0.50 (95% confidence interval [CI] 0.32-0.79) for moderate fitness, and OR of 0.32 (95% CI 0.21-0.51) for high fitness was seen. For T-score ≤ -2.5 at the FN, OR was 0.30 (95% CI 0.11-0.80) for moderate fitness, and OR was 0.29 (95% CI 0.12-0.71) for high fitness.
  
  
  CONCLUSIONS
  Increased CRF levels are associated with reduced risk for low bone density in postmenopausal women.
authors.affiliation: 1 The Cooper Institute , Dallas, Texas.
authors.forename: Laura F
authors.initials: LF
authors.lastname: DeFina
authors.affiliation: 1 The Cooper Institute , Dallas, Texas.
authors.forename: David
authors.initials: D
authors.lastname: Leonard
authors.affiliation: 1 The Cooper Institute , Dallas, Texas.
authors.forename: Benjamin L
authors.initials: BL
authors.lastname: Willis
authors.affiliation: 1 The Cooper Institute , Dallas, Texas.
authors.forename: Carolyn E
authors.initials: CE
authors.lastname: Barlow
authors.affiliation: 1 The Cooper Institute , Dallas, Texas.
authors.forename: Carrie E
authors.initials: CE
authors.lastname: Finley
authors.affiliation: 2 Laura W. Bush Institute for Women's Health, Texas Tech University Health Sciences Center , Lubbock, Texas.
authors.forename: Marjorie R
authors.initials: MR
authors.lastname: Jenkins
authors.affiliation: 3 Department of Pathology, Texas Tech University Health Sciences Center , Lubbock, Texas.
authors.forename: Barbara C
authors.initials: BC
authors.lastname: Pence
authors.affiliation: 4 Department of Community and Family Medicine, Texas Tech University Health Sciences Center , Lubbock, Texas.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: 5 Healthcare Engineering Program, Department of Mechanical Engineering, Texas Tech University , Lubbock, Texas.
authors.forename: Ming-Chien
authors.initials: MC
authors.lastname: Chyu
authors.affiliation: 6 New Mexico Clinical Research & Osteoporosis Center , Albuquerque, New Mexico .
authors.forename: E Michael
authors.initials: EM
authors.lastname: Lewiecki
authors.affiliation: 2 Laura W. Bush Institute for Women's Health, Texas Tech University Health Sciences Center , Lubbock, Texas.|3 Department of Pathology, Texas Tech University Health Sciences Center , Lubbock, Texas.
authors.forename: Chwan-Li
authors.initials: CL
authors.lastname: Shen
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology*; D000072599:Cardiorespiratory Fitness / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D005272:Femur Neck / Q000473:pathology*; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D010024:Osteoporosis / Q000175:diagnosis / Q000453:epidemiology*; D010809:Physical Fitness; D017698:Postmenopause; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D013781:Texas / Q000453:epidemiology
keywords: BMD; fitness; osteoporosis; risk