An observational study to examine how cumulative impact zones influence alcohol availability from different types of licensed outlets in an inner London Borough

OBJECTIVES: Cumulative impact zones (CIZs) are a widely implemented local policy intended to restrict alcohol availability in areas proliferated with licensed outlets. Limited previous research has questioned their effectiveness and suggested they may play a more nuanced role in shaping local alcohol environments. This study evaluates the association between CIZ implementation and the number of licence applications made, and the number issued, relative to a control region. DESIGN: A quantitative observational study. SETTING: The inner London Borough of Southwark, which currently enforces three CIZs. POPULATION: Licence applications received by Southwark Council’s Licensing Authority between 1 April 2006 and 31 March 2017 (n=1254). INTERVENTIONS: CIZ implementation. PRIMARY OUTCOME MEASURES: Five outlet types were categorised and evaluated: drinking establishments, eateries, takeaways, off sales and other outlets. Primary outcome measures were the number of applications received and the number of licences issued. These were analysed using Poisson regression of counts over time. RESULTS: Across all CIZs, implementation was associated with greater increases in the number of eateries in CIZ regions (incidence rate ratio (IRR)=1.58, 95% CI: 1.02–2.45, p=0.04) and number of takeaway venues (IRR=3.89, 95% CI: 1.32–11.49, p=0.01), relative to the control area. No discernible association was found for the remaining outlet types. Disaggregating by area indicated a 10-fold relative increase in the number of new eateries in Peckham CIZ (IRR=10.38, 95% CI: 1.39–77.66, p=0.02) and a fourfold relative increase in the number of newly licensed takeaways in Bankside CIZ (IRR=4.38, 95% CI: 1.20–15.91, p=0.03). CONCLUSIONS: CIZs may be useful as policy levers to shape local alcohol environments to support the licensing goals of specific geographical areas and diversify the night-time economy.