The distribution of harmful product marketing in public outdoor spaces and the effectiveness of marketing bans

Children's exposure to the marketing of harmful products in public outdoor spaces may influence their consumption of those products and affect health into adulthood. This study aimed to: i) examine the spatial distribution of children's exposure to three types of marketing-related `harms' (alcohol, unhealthy food, and gambling) in outdoor spaces in the Wellington region, New Zealand/Aotearoa; ii) compare differences in the distribution of harms by socioeconomic deprivation; and iii) estimate the effectiveness of different policies that ban such marketing. Data were from 122 children aged 11-13y who wore wearable cameras and GPS devices for four consecutive days from July 2014 to June 2015. Images were analysed to identify harmful product marketing exposures in public outdoor spaces. Eight policy scenarios were examined to identify the effectiveness of marketing bans, for all children and by socioeconomic deprivation. Children's ratio of harmful marketing was higher for children from high deprivation households and was also found to cluster, with hots spots observed around city centers. The effectiveness of marketing bans depended on the target setting and ban area, with banning 400 m around bus stops leading to the largest reduction. Effectiveness varied also by type of harm and socioeconomic deprivation. For example, banning alcohol marketing in residential areas was estimated to have a larger effect on exposure reduction for children from high deprivation households. Our findings suggest that alcohol, unhealthy food and gambling marketing often cluster outdoors and that targeted bans of such marketing would likely improve child health and, for some banning scenarios, promote equity.