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Quantifying leisure physical activity and its relation to bone density and strength
Kristine M Shedd1, Kathy B Hanson, D Lee Alekel
1Nutrition Department, University of California, Davis, CA 95616, USA.
Medicine and Science in Sports and Exercise
|November 30, 2007
Summary
Physical activity quantification methods showed varied associations with bone health in postmenopausal women. Leisure activity duration may be key for maintaining cortical bone density and offsetting age-related bone loss.
Area of Science:
- Bone biology and physical activity research.
- Gerontology and osteoporosis studies.
Background:
- Understanding the relationship between physical activity and bone health is crucial for preventing osteoporosis.
- Existing methods for quantifying physical activity may have differential associations with bone density and strength.
Purpose of the Study:
- To compare three physical activity quantification methods: total activity, peak strain, and bone-loading exposure (BLE) scores.
- To identify associations between these physical activity measures and bone health indicators, including areal bone mineral density (aBMD), volumetric BMD (vBMD), and bone strength.
Main Methods:
- 239 postmenopausal women from Iowa (ISU) and California (UCD) participated.
- Physical activity was assessed using the Paffenbarger Physical Activity Questionnaire, scored by three methods.
- Bone health was evaluated using dual-energy x-ray absorptiometry (DXA) for aBMD and peripheral quantitative computed tomography (pQCT) for vBMD and bone strength.
Main Results:
- No physical activity method correlated with areal bone mineral density (aBMD).
- Peak strain score showed negative associations with tibial bone strength indicators, while total activity score positively associated with femoral cortical bone.
- Geographic site influenced associations: ISU women showed negative associations between peak strain/hip BLE and bone measures, whereas UCD women had positive associations between total activity and femoral bone measures.
Conclusions:
- Leisure activity duration appears to be an important factor influencing physical activity's effect on bone.
- Higher leisure physical activity, assessed by total activity score, is linked to better cortical bone measures in postmenopausal women.
- This suggests physical activity could be a modifiable lifestyle factor to mitigate age-related bone loss.
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