PURPOSE: To compare associations of current and past self-reported bone-specific physical activity, and current accelerometer-determined physical activity (PA), with bone structure (bone mineral density [BMD] and microarchitecture) in postmenopausal women with osteopenia or osteoporosis.
METHODS: 50 community-dwelling postmenopausal women (mean age 64.4±7.7) with hip or spine BMD T-score ≤-1.0 SD were recruited for an exercise intervention. At baseline, current, past and total Bone-specific Physical Questionnaire (BPAQ) scores were self-reported, and percentages of sedentary, light and moderate to vigorous PA (MVPA) were objectively-determined by accelerometer measurements. Bone structure was assessed by lumbar spine and hip dual-energy X-ray absorptiometry (DXA), 3D modelling algorithms (3D-SHAPER) of hip DXA scans and distal tibial high-resolution peripheral quantitative computed tomography (HR-pQCT) scans.
RESULTS: Current BPAQ scores and MVPA were significantly positively associated with femoral neck areal BMD (β=0.315, p=0.031 and β=0.311, p=0.042, respectively) following multivariable adjustments. Current BPAQ scores were also positively associated with femoral cortical surface BMD (β=0.303, p=0.040) and volumetric BMD (β=0.343, p=0.019). Past and total BPAQ scores demonstrated positive associations with tibial trabecular number (β=0.334, p=0.022 and β=0.326, p=0.026, respectively), and negative associations with trabecular separation (β=-0.308, p=0.036 and β=-0.295, p=0.045, respectively) and distribution (β=-0.304, p=0.038 and β=-0.291, p=0.047, respectively). Current BPAQ scores and MVPA were positively associated with tibial cortical periosteal perimeter (β=0.295, p=0.046 and β=0.334, p=0.029, respectively).
CONCLUSION: Greater self-reported past PA appears to have lasting benefits for tibial trabecular microarchitecture, while current PA is positively associated with both femoral neck areal BMD and cortical bone in older women.