| Title: | Association between physical activity and body fat percentage, with adjustment for BMI: a large cross-sectional analysis of UK Biobank |
| Journal: | BMJ Open |
| Published: | 24 Mar 2017 |
| Pubmed: | https://pubmed.ncbi.nlm.nih.gov/28341684/ |
| DOI: | https://doi.org/10.1136/bmjopen-2016-011843 |
| URL: | https://bmjopen.bmj.com/content/bmjopen/7/3/e011843.full.pdf |
Publication 4154
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Abstract
OBJECTIVES: The objective of this study was to examine if, in the general population, physically active adults have less body fat after taking body mass index (BMI) into account.</p>
DESIGN: A cross-sectional analysis of participants recruited into UK Biobank in 2006-2010.</p>
SETTING: UK Biobank assessment centres throughout the UK.</p>
PARTICIPANTS: 119 230 men and 140 578 women aged 40-69 years, with complete physical activity information, and without a self-reported long-term illness, disability or infirmity.</p>
EXPOSURES: Physical activity measured as excess metabolic equivalent (MET)-hours per week, estimated from a combination of walking, and moderate and vigorous physical activity. BMI from measured height and weight.</p>
MAIN OUTCOME MEASURE: Body fat percentage estimated from bioimpedance.</p>
RESULTS: BMI and body fat percentage were highly correlated (r=0.85 in women; r=0.79 in men), and both were inversely associated with physical activity. Compared with <5 excess MET-hours/week at baseline, ≥100 excess MET-hours/week were associated with a 1.1 kg/m2 lower BMI (27.1 vs 28.2 kg/m2) and 2.8 percentage points lower body fat (23.4% vs 26.3%) in men, and 2.2 kg/m2 lower BMI (25.6 vs 27.7 kg/m2) and 4.0 percentage points lower body fat (33.9% vs 37.9%) in women. For a given BMI, greater physical activity was associated with lower average body fat percentage (for a BMI of 22.5-24.99 kg/m2: 2.0 (95% CI 1.8 to 2.2), percentage points lower body fat in men and 1.8 (95% CI 1.6 to 2.0) percentage points lower body fat in women, comparing ≥100 excess MET-hours per week with <5 excess MET-hours/week).</p>
CONCLUSIONS: In this sample of middle-aged adults, drawn from the general population, physical activity was inversely associated with BMI and body fat percentage. For people with the same BMI, those who were more active had a lower body fat percentage.</p>
5 Authors
- Kathryn E Bradbury
- Wenji Guo
- Benjamin J Cairns
- Miranda E G Armstrong
- Timothy J Key
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