Change in advertising exposure of unhealthy commodities after the implementation of an outdoor advertising restrictions policy in Bristol, UK: a descriptive study

In 2021, Bristol, UK, implemented a city-wide policy restricting advertising of unhealthy commodities on council-owned sites. We aimed to describe advertising exposure before and after the implementation of the policy in Bristol. We collected data from bus shelters in Bristol (N=283) and neighbouring South Gloucestershire (SG, comparator, N=65), using in-person and Google Street View audits, before (T0, 02/2022 – 07/2022) and after (T1, 04/2023 – 07/2023 and T2, 11/2023 – 02/2024) policy implementation. We captured unhealthy commodity adverts on display; high in fat, sugar or salt (HFSS) products (defined using the UK Nutrient Profiling Model), alcohol, gambling or payday loans; information on brands; whether they appealed to children or adolescents and split analyses by area deprivation and proximity to schools. At T0, unhealthy commodity advertising in both areas was relatively low, however the policy successfully reduced unhealthy commodity advertising in Bristol at T2 (11.3% to 0.8%), compared to an increase in SG (0.9% to 18.1%). Most restricted adverts in both areas displayed HFSS products (ranging 60-100%), especially fast food, with limited alcohol and gambling and no payday loan advertising observed. A few adverts displaying non-compliant products were maintained in Bristol but advertisers also switched to advertising alternative, compliant products. Minimal unhealthy commodity advertising appealed to children/adolescents (1.1-8.8%) or appeared within 100m of schools (N=2 adverts), and no clear association with area deprivation was found. Findings suggest the need for formal monitoring processes to ensure policy adherence and assess unhealthy commodity advertising in the entire outdoor space to inform potential expansion of such policies.