882Relationship of Urban Sprawl with Overweight and Obesity: Roles of Physically-Active and Sedentary Travel Behaviours

Abstract

Abstract Background Urban sprawl – low-density neighbourhood developments at the city’s periphery – is related to risk of overweight/obesity. Our mediation analysis examined the extent to which this relationship may be explained by physically-active and sedentary travel behaviours. Methods We analysed data from 2,465 metropolitan residents in the 2011-12 wave of the Australian Diabetes, Obesity and Lifestyle Study. Urban sprawl measure was geographic information system derived residential proximity to the major city centre. Self-reported weekly frequency of walking for transport (WT) and car driving duration (car use) were used as measures of physically-active and sedentary travel behaviours. Risk of overweight/obesity was calculated using objectively-measured body mass index (> 25 kg/m2). Multi-level regression models and joint-significance mediation tests were used. Results Residing near the city centre was associated with higher levels of WT and lower levels of car use. For instance, compared to those living within 10km from the city centre, those living over 30km away had 57% lower WT frequency (p<0.001) and 1.4 hours/week more car use (p=0.002). In turn, lower levels of WT and higher levels car use were associated with elevated overweight/obesity risk. Conclusions These analyses suggest that travel behaviors can be potential mediators in relationships of urban sprawl with overweight/obesity. Future studies are warranted to assess causality of these relationships. Key messages Urban planning policies need to consider these impacts of the expansion of urban sprawl and promote inner-city high-density development by encouraging more physically-active travel and less time spent sitting in cars to reduce the population burden of overweight/obesity.