A quantitative study on the impact of a new outdoor advertising restrictions policy in Bristol (UK)

Background Bristol was the first city outside London to introduce a policy to restrict adverts for high fat, salt and sugar (HFSS) products and other unhealthy commodities (alcohol, gambling, payday loans) on council sites in 2021. This research evaluates the impact of this policy. Methods We conducted a controlled repeated cross-sectional study of Bristol (intervention) and neighbouring South Gloucestershire (control) residents before (n = 2,543) and after (n = 2,043) the policy came into effect. Self-reported exposure to adverts of HFSS products, alcohol and gambling and consumption/use of these products was collected. The intervention effect was analysed using a weighted controlled before-after design. In addition, we analysed 2020-23 timeseries of foods and drinks purchased by 1,012 households from Bristol (n = 217) and control areas (n = 795) from Kantar’s Worldpanel Take Home data. A controlled interrupted time series design was used to estimate the impact of the policy on weekly household purchases of energy and nutrients from HFSS products. Results Preliminary results did not indicate significant changes in exposure to unhealthy commodity adverts or consumption/use of unhealthy commodities post-intervention. However, the majority of results suggested a potential reduction; with for example a -22.1 (95% CI -47.3, 16.2) percentage point decrease in reported consumption of fast-food compared to controls. We also did not observe significant differences in weekly energy purchased from HFSS products compared to counterfactual; 897.6Kcal, 95%CI -57.7, 1,853.0, nor in purchases of fat (39.0g, 95%CI -20.1, 98.1), sugar (48.0g, 95%CI -19.8, 115.7) or salt (-0.4g, 95%CI -4.1, 3.2) from HFSS products. Conclusions Preliminary results indicate the new policy had no clear impact on exposure to unhealthy commodity adverts or purchasing and consumption of HFSS products. This may be attributable to the relatively small amount of total advertisement space owned by Bristol City Council (∼30%). Key messages • Policies restricting adverts of HFSS products and other unhealthy commodities are potentially effective tools to improve diet and to reduce diet-related diseases and public health inequalities. • We did not observe a measurable impact of this policy in Bristol, which may be attributable to the relatively small Council-owned advertisement estate within the total available advertisement space.