Quantifying Children's Exposure to Outdoor Food Advertising

Abstract

The marketing of unhealthy food is a key modifiable influence on children’s dietary behaviours and childhood obesity. The WHO Commission on Ending Childhood Obesity (ECHO) has recommended that settings where children gather be free of unhealthy food marketing. Internationally, there are no data available that quantify children’s exposure to outdoor food advertising in public places. This study investigated the extent and nature of children’s exposure to outdoor food advertising overall, and on the journey to and from school. A random sample of 168 children (aged 11-13y) from 16 randomly selected schools in Wellington, New Zealand wore cameras that took pictures automatically every 7s and a GPS device for four days. Using bespoke software, images were coded for outdoor food advertising using a pre-determined coding schedule. The advertised food products were classified as ‘core’ or ‘non-core’ using an accepted nutrient profiling system. The rate of core and non-core outdoor advertising exposures on journeys to and from school, and outside of school hours, were analysed overall, and by ethnicity and socioeconomic deprivation. Overall, children were exposed to a mean of 8.3 food advertisements for each hour they spent in outdoor settings. Of these advertisements, 7.4 (89.2%) were for non-core and 0.8 (9.6%) were for core food advertisements. Exposure to non-core outdoor food advertising was highest among Māori participants. The most frequent non-core exposures were advertisements for fast food, sweet drinks, ice creams, and cookies. Both non-core and core advertising exposures were concentrated around food outlets, convenience stores, and on main roads. On the journey to and from school, the extent of children’s exposure to non-core and core advertising was associated with the presence of convenience stores and shopping areas along the routes they travelled. To our knowledge, this is the first study internationally to objectively document and quantify the rate at which children encounter outdoor food advertising. The findings of this research suggest that outdoor food advertising is a significant source of children’s exposure to non-core food advertising, irrespective of whether they are the target audience. This research suggests that to reduce the extent and power of food advertising, as recommended by the ECHO report, urgent action must be taken by local government to remove unhealthy food advertisements from public places, particularly along major roadways and at shop fronts. This work extends previous research by providing evidence that children are exposed to unhealthy food advertising, not only in the places where they are known to gather but also across the spectrum of their everyday environments. Further, this research highlights that the advertising standards codes that regulate the promotion of food to New Zealand children are inadequate and must be strengthened to protect children from harmful food advertising. Implementing these measures would likely reduce the influence of food advertising on children and should be included as part of a comprehensive strategy to address childhood obesity in New Zealand. Although this study was conducted in New Zealand, the findings of this research are likely relevant for policy makers in other jurisdictions as outdoor advertising is a prominent feature in many cities across the world. Restricting outdoor advertising in cities and urban areas would, as part of a comprehensive strategy, likely improve dietary behaviours, reduce childhood obesity, and improve population health outcomes.