Activity, body composition and bone health in children
- Kathy Kennedy1,
- Sheila Shepherd2,
- Jane E Williams1,
- S Faisal Ahmed3,
- Jonathan C Wells1,
- Mary Fewtrell1
- 1Nutrition Unit, UCL Institute of Child Health, London, UK
- 2Paediatric Bone Densitometry Service, Yorkhill Hospitals, Glasgow, UK
- 3School of Medicine, University of Glasgow, Glasgow, UK
- Correspondence to Kathy Kennedy, Nutrition Unit, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK;
- Received 4 September 2012
- Revised 26 November 2012
- Accepted 26 November 2012
- Published Online First 25 December 2012
Objective To examine relationships among daily activity levels, body composition and bone outcomes in children aged 6.7 years who were born at term with birth weights <20th centile.
Methods Activity data collected using accelerometers were correlated with body composition and bone outcome z-scores from dual-energy X-ray absorptiometry in 36 children.
Results Activity levels were related to body composition outcomes; for example, lean mass index (lean mass/height2) was positively associated with time spent in moderate activity (r=0.40, p=0.02) and negatively with time spent in sedentary activity (r=−0.50, p=0.002). Per cent time spent in sedentary activity correlated negatively with whole body bone mineral density z-score (r=−0.44, p=0.01) and hip bone mineral content (r=−0.38, p=0.03).
Conclusions Moderate and vigorous activity levels were associated with increased lean and bone mass in this population but not with conventional measures of adiposity such as weight and body mass index z-scores. Standard measures of adiposity may mask potential benefits of regular activity.