E-Poster Presentation 30th Australian and New Zealand Bone and Mineral Society Annual Scientific Meeting 2020

Estimating the osteogenic potential of physical activity and its associations with five-year bone mineral density changes, incident falls and fractures in older men (#109)

Carrie-Anne Ng 1 , David Scott 1 2 3 , Markus J Seibel 4 , Robert G Cumming 5 6 7 , Vasi Naganathan 6 , Fiona M Blyth 6 , David G Le Couteur 6 8 , Louise M Waite 6 , David J Handelsman 9 , Vasant Hirani 5 6 10
  1. Department of Medicine, School of Clinical Sciences at Monash Health, Monash University, Clayton, Victoria, Australia
  2. Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria, Australia
  3. Department of Medicine at Western Health, The University of Melbourne, Sunshine, Victoria, Australia
  4. Bone Research Program, ANZAC Research Institute, The University of Sydney, Concord Campus, Sydney, New South Wales, Australia
  5. School of Public Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
  6. Centre for Education and Research on Ageing, Concord Hospital, University of Sydney, Sydney, New South Wales, Australia
  7. The ARC Centre of Excellence in Population Ageing Research, University of Sydney, Sydney, New South Wales, Australia
  8. ANZAC Research Institute & Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia
  9. Department of Andrology, Concord Hospital & ANZAC Research Institute, University of Sydney, Sydney, New South Wales, Australia
  10. School of Life and Environmental Sciences, Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia

OBJECTIVE: Physical activity which generates high bone strain may benefit bone health and reduce fracture risk. This study aimed to investigate the relationships between force intensities and application rate estimated from self-reported physical activity with (1) changes in bone mineral density (BMD) over five years, (2) incident falls over two years and (3) long-term incident fractures in older men.

METHODS: 1613 men (mean age 76.8±5.4) from the Concord Health and Ageing in Men Project (CHAMP) were assessed at baseline, 2-year follow-up and 5-year follow-up. At each time point, hip and lumbar spine BMD were estimated by dual-energy x-ray absorptiometry, and physical activity was self-reported using the Physical Activity Scale for the Elderly (PASE) questionnaire. Sum effective load ratings (ELRs) and peak force were computed from the PASE questionnaire reflecting the total and highest intensity and frequency of ground reaction forces for physical activity modalities respectively. Participants were contacted over two years to self-report incident falls, and over 6.0±2.2 years for fractures.

RESULTS: Compared to sum ELR and PASE scores, peak force demonstrated the greatest standardised effect size of BMD increases at the spine (β=9.77mg/cm2) and total hip (β=14.14mg/cm2) after adjustment for covariates including PASE components (all p<0.01). Only PASE scores were significantly associated with reduced falls risk (incident rate ratio=0.89 per standard deviation, p=0.03). In adjusted categorical analyses, only high peak force was significantly associated with decreased risk of any self-reported fractures compared to low peak force (hazard ratio=0.60, 95% confidence interval=0.35, 0.99).

CONCLUSION: Older men who engage in physical activity of sufficiently high and rapid impact maintain higher BMD and have reduced fracture risk, while physical activity of high metabolic expenditure reduced falls risk. Coupling traditional physical activity questionnaire outcomes with bone-loading estimates may improve understanding of relationships between physical activity and bone health in older adults.