E-Poster Presentation ESA-SRB-ANZBMS 2021

Osteogenic potential of physical activities and their associations with bone mass in young adults from the Raine Study (#751)

Carrie-Anne Ng 1 , David Scott 1 2 , Marc Sim 3 4 5 6 , Kun (Kathy) Zhu 4 7 , Aris Siafarikas 4 5 6 8 9 10 , Nicolas Hart 5 6 10 11 , Jocelyn Tan 5 12 , Paola Chivers 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. Institute for Nutrition Research, Edith Cowan University, Joondalup, Western Australia, Australia
  4. Paediatrics, Medical School, The University of Western Australia, Perth, Western Australia, Australia
  5. Western Australia Bone Research Collaboration, Perth, Western Australia, Australia
  6. School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
  7. Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
  8. Department of Endocrinology and Diabetes, Perth Children's Hospital, Perth, Western Australia, Australia
  9. Telethon Kids Institute for Health Research, Perth, Western Australia, Australia
  10. Institute for Health Research, The University of Notre Dame Australia, Fremantle, Western Australia, Australia
  11. Centre for Healthcare Transformation, Queensland University of Technology, Brisbane, Queensland, Australia
  12. School of Nursing, Midwifery, Health Sciences and Physiotherapy, The University of Notre Dame Australia, Fremantle, Western Australia, Australia

Physical activity questionnaires utilised in research generally assess metabolic equivalents of task (METs). It is unclear whether mechanical loading during physical activity, estimated from METs-based questionnaires, is associated with skeletal health. This cross-sectional study investigated how physical activity of high loading intensities and rates, assessed at ages 17- and 20-years, (a) compares with physical activity measured in METs, and (b) is associated with bone mass at age 20 years. 826 participants from the Raine Study Gen2 were assessed for physical activity energy expenditure over the past week via the International Physical Activity Questionnaire (IPAQ) at age 17- and 20-years. Loading scores (the product of peak force and application rate of an activity) per week were subsequently estimated from the IPAQ. Whole-body and appendicular bone mineral density (BMD) at age 20-years were assessed by dual-energy X-ray absorptiometry. Bland-Altman minimal detectable difference for physical activity Z-scores at age 17- and 20-years were 1.59 standard deviations (SDs) and 1.33 SDs respectively; greater than the a priori minimal clinically important change of 0.5 SDs. Loading score at age 17- and 20-years, but not IPAQ score, had significant positive associations with whole-body and leg BMD after adjustment for covariates (β=0.008 and 0.012g/cm2 respectively). IPAQ score at age 20-years, but not loading score, had a significant positive association with arm BMD (β=0.007g/cm2). There was no significant association between 3-year change in IPAQ or loading score and bone mass. This study revealed disagreement in associations of self-reported METs and loading score estimates with bone health in young adults. Participation in physical activity with higher loading scores was associated with whole-body and leg BMD, while higher energy expenditure was associated with arm BMD. Coupling traditional energy expenditure questionnaire outcomes with bone-loading estimates may improve understanding of the location-specific skeletal benefits of physical activity in young adults.