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Published on: January 29, 2018
Does reduced skeletal loading account for age-related bone loss?
L Joseph Melton1, B Lawrence Riggs, Sara J Achenbach
1Division of Epidemiology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA.
Summary
Age-related bone loss is not solely caused by reduced physical activity and muscle mass. This study found no close link between these factors and bone strength changes in adults, suggesting simpler theories are insufficient.
Area of Science:
- Gerontology
- Bone Biology
- Biomechanics
Background:
- Age-related bone loss is a significant health concern.
- A leading theory posits reduced physical activity and muscle mass as primary causes.
- This hypothesis lacks detailed investigation in diverse populations.
Purpose of the Study:
- To investigate the relationship between habitual skeletal loading and age-related changes in bone strength.
- To test the hypothesis that bone strength per unit load does not vary with age.
- To examine cross-sectional data from a population-based sample of men and women.
Main Methods:
- A stratified random sample of 375 women and 325 men (age 21-97) from Rochester, MN, was studied.
- Bone strength indices (flexural rigidity, axial rigidity) were measured using QCT and pQCT.
- Habitual skeletal loading was assessed via lean body mass, total skeletal muscle mass (TSM), body weight, and physical activity.
Main Results:
- The null hypothesis of no age-related change in strength-to-load ratios was rejected in 72% of cases.
- Femoral neck strength-to-TSM ratio increased annually in both women and men.
- No consistent correspondence was found between changes in habitual load and bone strength.
Conclusions:
- Reduced skeletal loading is likely an oversimplified explanation for age-related bone loss.
- Substantial interindividual variation exists in strength-to-load ratios.
- Bone strength adaptation to loading may be more complex than previously theorized.
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