Background: Physical inactivity is a leading cause of obesity and premature mortality. We aimed to examine the relation between active commuting and obesity in mid-life using objectively measured anthropometric data from UK Biobank.
Methods: Cross-sectional, observational data from UK Biobank were used. These were collected from individuals aged 40-69 years who visited 22 assessment centres across the UK between 2006 and 2010. Self-reported commuting method was operationalised into seven categories, ordered to refl ect typical levels of physical exertion. The outcomes assessed were BMI (based on objectively measured weight and height) and percentage body fat. Hypothesised confounders were income, area deprivation, urban or rural residence, education, alcohol intake, smoking, leisure physical activity, recreational walking, occupational physical activity, general health, and limiting illness or disability. We used sex-stratifi ed multivariate linear-regression models.
Findings: Final complete case sample sizes were 72 999 men and 83 667 women for the BMI outcome and 72 139 men and 82 788 women for the percentage body fat outcome. Active commuting was signifi cantly and independently associated with reduced BMI and percentage body fat for both sexes, with a graded pattern apparent across the seven commuting categories. In fully adjusted models, compared with their car-only counterparts, mixed public and active transport commuters had signifi cantly lower BMI (men: coeffi cient 1 00 kg/m [95% CI 1 14 to 0 87], p<0 0001; women: 0 67 kg/m [ 0 86 to 0 47], p<0 0001), as did cycling or cycling and walking commuters (men: 1 71 kg/m [95% CI 1 86 to 1 56], p<0 0001; women: 1 65 kg/m [ 1 92 to 1 38], p<0 0001). Similarly, compared with car-only commuters, mixed public transport and active commuters had signifi cantly lower percentage body fat (men: 1 32% [95% CI 1 53 to 1 12], p<0 0001; women: 1 10% [ 1 40 to 0 81], p<0 0001), as did cycling or cycling and walking commuters (men: 2 75% [95% CI 3 03 to 2 48], p<0 0001; women: 3 26% [ 3 80 to 2 71], p<0 0001).
Interpretation: This study is the fi rst to use UK Biobank data to address the topic of active commuting and obesity and shows robust, independent associations between active commuting and healthier bodyweight and composition. These findings support the case for interventions to promote active travel as a population-level policy response for prevention of obesity in mid-life.
Flint E, Cummins S (2016) Active commuting and obesity in mid-life: cross-sectional, observational evidence from UK Biobank, The Lancet Diabetes & Endocrinology, Volume 4, Issue 5, May 2016, Pages 420-435, ISSN 2213-8587
Investigating the relationship between active commuting and cardiovascular disease
The beneficial effects of physical activity on cardiovascular disease (CVD) outcomes are well understood. Among Western populations however, lifestyles have become increasingly sedentary. Active commuting (AC) (walking/cycling for some/all of the journey between home and work) is recommended by NICE as a way of incorporating greater levels of physical activity into daily life. However, while current evidence generally suggests an association between AC and good health, the strength of this evidence is varied and the nature of the relationship remains unclear.
This project will take a systematic, sequential approach to exploring the impact of AC on CVD. The outcomes can be split into 3 categories, reflecting their position on the causal pathway: (i) Biological antecedents of CVD (anthropometric measures including BMI and blood pressure); (ii) Diagnosed CVD conditions (hospital in-patient data, and primary care data to be requested when available); (iii) CVD mortality (death registry).
Flint E, Webb E, Cummins S. Change in commute mode and body mass index: prospective longitudinal evidence from UK Biobank. The Lancet Public Health 2016; 1(2):e46-e55 http://thelancet.com/journals/lanpub/article/PIIS2468-2667(16)30006-8/fulltext
Flint E, Cummins S (2016) Active commuting and obesity in mid-life: cross-sectional, observational evidence from UK Biobank, The Lancet Diabetes & Endocrinology, Volume 4, Issue 5, May 2016, Pages 420-435, ISSN 2213-8587, https://doi.org/10.1016/S2213-8587(16)00053-X. (http://www.sciencedirect.com/science/article/pii/S221385871600053X)
|Lead investigator:||Dr. Ellen Flint|
|Lead institution:||London School of Hygiene and Tropical Medicine|