Associations between active commuting, body fat, and body mass index: population based, cross sectional study in the United KingdomBMJ 2014; 349 doi: https://doi.org/10.1136/bmj.g4887 (Published 19 August 2014) Cite this as: BMJ 2014;349:g4887
- Ellen Flint, research fellow1,
- Steven Cummins, professor of population health1,
- Amanda Sacker, professor of lifecourse studies2
- 1Department of Social and Environmental Health Research, London School of Hygiene and Tropical Medicine, London WC1H 9SH, UK
- 2ESRC International Centre for Lifecourse Studies in Society and Health, Research Department of Epidemiology and Public Health, University College London, London WC1E 6BT, UK
- Correspondence to: E Flint
- Accepted 15 July 2014
Objective To determine if promotion of active modes of travel is an effective strategy for obesity prevention by assessing whether active commuting (walking or cycling for all or part of the journey to work) is independently associated with objectively assessed biological markers of obesity.
Design Cross sectional study of data from the wave 2 Health Assessment subsample of Understanding Society, the UK Household Longitudinal Study (UKHLS). The exposure of interest, commuting mode, was self reported and categorised as three categories: private transport, public transport, and active transport.
Participants The analytic samples (7534 for body mass index (BMI) analysis, 7424 for percentage body fat analysis) were drawn from the representative subsample of wave 2 respondents of UKHLS who provided health assessment data (n=15 777).
Main outcome measures Body mass index (weight (kg)/height (m)2); percentage body fat (measured by electrical impedance).
Results Results from multivariate linear regression analyses suggest that, compared with using private transport, commuting by public or active transport modes was significantly and independently predictive of lower BMI for both men and women. In fully adjusted models, men who commuted via public or active modes had BMI scores 1.10 (95% CI 0.53 to 1.67) and 0.97 (0.40 to 1.55) points lower, respectively, than those who used private transport. Women who commuted via public or active modes had BMI scores 0.72 (0.06 to 1.37) and 0.87 (0.36 to 0.87) points lower, respectively, than those using private transport. Results for percentage body fat were similar in terms of magnitude, significance, and direction of effects.
Conclusions Men and women who commuted to work by active and public modes of transport had significantly lower BMI and percentage body fat than their counterparts who used private transport. These associations were not attenuated by adjustment for a range of hypothesised confounding factors.
Understanding Society (UKHLS) is an initiative by the Economic and Social Research Council, with scientific leadership by the Institute for Social and Economic Research, University of Essex, survey delivery by the National Centre for Social Research, and survey management by the UK Data Archive.
Contributors: The study was conceived of and planned by all authors. EF undertook the data analysis and interpretation, assisted by AS. EF drafted the manuscript. All authors edited the manuscript and approved the final version. Professor Paul Clarke, University of Essex, is thanked for his methodological advice.
Funding: SC and EF are supported by a UK National Institute of Health Research (NIHR) Senior Fellowship to SC. AS is supported by the UK Economic and Social Research Council (ESRC) ES/J019119/1. The authors affirm their independence from these funders. The funders played no part in the study design, collection, analysis or interpretation of data, or in the writing of the report, or in the decision to submit the article for publication. The views and opinions expressed herein are those of the authors and do not necessarily reflect those of the NIHR or the UK Department of Health.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: Not required for this secondary data analysis project. The Understanding Society study has been approved by the University of Essex ethics committee. Approval from the National Research Ethics Service was obtained for the collection of biosocial data by trained nurses in wave 2 and of the main Understanding Society survey.
Transparency: The lead author, EF, affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been explained. All authors had full access to all of the data in the study and can take responsibility for the integrity of the data and the accuracy of the data analysis.
Data sharing: The UK Household Longitudinal Study dataset is available under End User License from the UK Data Archive (http://discover.ukdataservice.ac.uk/series/?sn=2000053.)
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