Background: Insuffi cient physical activity is a determinant of obesity and cardiovascular disease. Active travel to work has declined in high-income countries in recent decades. We aimed to determine which socioeconomic and demographic characteristics predicted switching to or from active commuting, whether switching from passive to active commuting (or the reverse) independently predicts change in objectively measured body-mass index (BMI), and to ascertain whether any association is attenuated by socioeconomic, demographic, or behavioural factors.
Methods: This study used longitudinal data from UK Biobank. Baseline data collection occurred at 22 centres between March, 2006, and July, 2010, with a repeat assessment at one centre (Stockport) between August, 2012, and June, 2013, for a subset of these participants. Height and weight were objectively measured at both timepoints. We included individuals present at both timepoints with complete data in the analytic sample. Participants were aged 40 69 years and commuted from home to a workplace on a regular basis at both baseline and follow-up. Two exposures were investigated: transition from car commuting to active or public transport commuting and transition from active or public transport to car commuting. Change in BMI between baseline and repeat assessment was the outcome of interest, assessed with bivariate and multivariate logistic regression models.
Findings: 502 656 individuals provided baseline data, with 20 346 participating in the repeat assessment after a median of 4 4 years (IQR 3 7 4 9). 5861 individuals were present at both timepoints and had complete data for all analytic variables. Individuals who transitioned from car commuting at baseline to active or public transportation modes at follow-up had a decrease in BMI of 0 30 kg/m (95% CI 0 47 to 0 13; p=0 0005). Conversely, individuals who transitioned from active commuting at baseline to car commuting at follow-up had a BMI increase of 0 32 kg/m (0 13 to 0 50; p=0 008). These eff ects were not attenuated by adjustment for hypothesised confounders. Change in household income emerged as a determinant of commute mode transitions.
Interpretation: Incorporation of increased levels of physical activity as part of the commute to work could reduce obesity among middle-aged adults in the UK.
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
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|