Abstract
Using active transport modes to and from school (ATS) (solely or combined with motorised transport) has the potential to increase physical activity (PA), which is a desirable health behaviour in adolescents. However, travelling to and from school may pose a risk of exposure to an obesogenic environment, particularly when using ATS, whereby young people may have visual and spatial access to the adjacent food environment. Under such conditions, adolescents may have increased opportunities for purchasing and consuming unhealthy snack food or soft drinks during their school journey. Thus, when ATS is used in part, or for the entire school journey through a suboptimal food environment, there is a potentially detrimental impact on health through increased unhealthy snacking. The aim of this study is to examine adolescents’ unhealthy snacking behaviour during their journey to and from school. This includes investigating the relationship between adolescents’ purchase and consumption of unhealthy snack food and soft drinks when using different school transport modes and the food environment during the school journey.
Adolescents (n=2773) from 23 of the 27 secondary schools in Dunedin city– Ōtepoti and the Otago region–Ōtākou, Aotearoa New Zealand, were surveyed and their sociodemographic characteristics, school transport modes, health behaviours, food habits, and perceptions of the school neighbourhood food environment were reported. For adolescents residing in Dunedin, objective measures of food outlets were generated using the estimated shortest school routes and within the 500 m and 1000 m school neighbourhood buffers using Geographical Information Systems (GIS). Food outlet data were retrieved using Google Places API and audited using virtual ground truthing.
Overall, about 22.5% and 42.5% of these adolescents purchased and consumed unhealthy snacks at least once per week on their way to and from school, respectively. Individual, social, and environmental factors were associated with adolescents’ unhealthy snacking behaviour during the school journey. A higher proportion of adolescents using mixed transport modes had unhealthy snacks and soft drinks during their school journey, compared to those using motorised or ATS only on the way to school (mixed/motorised/ATS: 28.6% / 18.8% / 21.2%; p = 0.012) and on the way from school (mixed/motorised/ATS: 8.4% / 42.1% / 35.5%; p = 0.030). When analysed separately by gender, the significant relationship between unhealthy snacking behaviour and school transport modes was found in girls only.
Among adolescents in Dunedin who attended schools located less than 4 km from where they lived, nearly half (44.8%) of them did not have any food outlets on their estimated shortest school route. Although food outlet availability on the estimated school route was positively associated with using mixed transport modes and home neighbourhood deprivation, no relationship was found between food outlet availability and unhealthy snacking behaviour. Food outlet availability in the school neighbourhood was higher for schools in the central city area and in neighbourhoods with high deprivation, compared to those outside the central city area and in neighbourhoods with low deprivation. Furthermore, the school neighbourhood food environment, particularly the distance to the nearest food outlets from school and perceived availability of food in their proximal environment had a significant inverse association with adolescents’ unhealthy snacking behaviour during the school journey.
To my knowledge, this is the first study to examine the association between school transport modes and adolescents’ unhealthy snacking behaviour, studied in relation to mixed transport modes in the transport categories. This is also the first research internationally to examine food outlets both along the adolescents’ school route and in the school neighbourhood concurrently. While unhealthy snacking during the school journey may only occur in a small window of time during the day, the potential of habit creation and impacts on health during this period could be significant. My findings provide insights into the environmental, social, and individual factors related to adolescents’ unhealthy snacking behaviours that may inform public health measures. The results suggest that food outlets and adolescents’ unhealthy snacking was related to school transport modes and neighbourhood deprivation. Addressing policies concerning zoning regulations for food outlets and implementing healthy food and drinks guidance in the school neighbourhood, may proportionally provide greater benefit for adolescents residing in or attending schools in more disadvantaged areas. The healthier the food environment through which adolescents travel to and from school, the easier it will be for them to choose healthy food options.