title: Associations between active commuting, body fat, and body mass index: population based, cross sectional study in the United Kingdom.
abstract: 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.
  
  
  METHODS
  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.
  
  
  METHODS
  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).
  
  
  METHODS
  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.
authors.affiliation: Department of Social and Environmental Health Research, London School of Hygiene and Tropical Medicine, London WC1H 9SH, UK ellen.flint@lshtm.ac.uk.
authors.forename: Ellen
authors.initials: E
authors.lastname: Flint
authors.affiliation: Department of Social and Environmental Health Research, London School of Hygiene and Tropical Medicine, London WC1H 9SH, UK.
authors.forename: Steven
authors.initials: S
authors.lastname: Cummins
authors.affiliation: ESRC International Centre for Lifecourse Studies in Society and Health, Research Department of Epidemiology and Public Health, University College London, London WC1E 6BT, UK.
authors.forename: Amanda
authors.initials: A
authors.lastname: Sacker
mesh_terms: D001642:Bicycling / Q000706:statistics & numerical data*; D050218:Body Fat Distribution; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D014186:Transportation / Q000379:methods* / Q000706:statistics & numerical data*; D006113:United Kingdom / Q000453:epidemiology; D016138:Walking / Q000706:statistics & numerical data*