866. Do active modes of transport cause lower body mass index? Findings from the HABITAT longitudinal study
Commentary by Sheree Hughes, Active Living Manager, National Heart Foundation of Australia
Research from The National Health and Medical Research Council (NHMRC) Centre of Research Excellence (CRE) in Healthy, Liveable Communities has produced these two papers looking at causal relationship between transport-related physical activity and bodyweight.
The papers use data from the HABITAT (How Areas in Brisbane Influence healTh And acTivity) study. HABITAT is a longitudinal multi-level study of physical activity among people aged 40+ years living in Brisbane. With over 11,000 participants and 200 neighbourhoods, it is one of the largest studies of its kind.
The two papers complement each other in that the causal inference analysis in original paper focuses on people who change their transport mode1 (e.g. from private motor vehicle to active modes), whereas the more recent paper focusses on people who do not change their mode and examines how the consistent use of active travel over seven years influences trends in self-reported Body Mass Index (BMI)2.
In the original paper1 the respondents were asked to report on their main transport for all purposes (work-related and non-work-related). Transport mode was measured as private motor vehicle, public transport, working or cycling and height and weight were self-reported. Adding to the evidence base, the findings of the study were that BMI was significantly lower for men and women who mainly walked or cycled when compared with respondents who mainly used private motor vehicles for transport. The powerful link in this longitudinal study though is the with-in-person change in BMI over time. The study found a with-in-person lowering in BMI when the respondent walked or cycled verses when they used a private motor vehicle. Similar positive associations with public transport use and BMI were not found.
The more recent paper2 examines whether the consistent use of active travel (walking and cycling) over a seven-year period helps mitigate the increases in overweight and obesity, that have been observed during the last few decades. The results showed that those who consistently walked or cycled had a lower BMI relative to those who consistently used a private motor vehicle.
These results are central to the advocacy efforts of health authorities who are calling for policies that promote active travel as a way of routinely incorporating physical activity into everyday life.
Turrell G, Hewitt BA, Rachele JN, et al. (2018) Do active modes of transport cause lower body mass index? Findings from the HABITAT longitudinal study J Epidemiol Community Health, 72:294-301.
Turrell G, Hewitt BA, Rachele JN, et al. (2018) Prospective trends in body mass index by main transport mode, 2007–2013. Journal of Transport & Health 8, 183-192.