What impact would tobacco retailer proximity limit have on tobacco availability in New Zealand?

Introduction One policy option to reduce the density of tobacco retailers is to restrict the distance retailers can be located to each other. This study examined the impacts of proximity limits of 150 m, 300 m and 450 m between tobacco retailers in New Zealand and if critical threshold reduction in tobacco retailers of 90%-95% would be achieved. Methods Using a spatial modelling approach, tobacco retailers were randomly removed based on a minimum distance between retailers until there were zero retailers within each scenario's minimum distance. This was repeated for all three proximity limit scenarios and descriptive statistics are provided for each. Results Implementation of 150 m, 300 m or 450 m distance restrictions between tobacco retailers would result in an average reduction in availability of 35%, 49% and 58%, respectively. On average, the current median distance to the closest retailer increases from 110 m to 377 m, to 568 m or to 718 m, respectively. The average median distance from a retailer to the closest school also increases across the three proximity limits, from 1017 m to 1087 m, to 1149 m or to 1231 m, respectively. Reduced clustering in deprived areas would be most apparent if a 450 m restriction policy was implemented. Conclusions A proximity limit of 450 m would reduce retailers by 58%, but would not reach proposed critical behaviour-change threshold of 90%-95% required to reduce smoking prevalence independently. There is a need for a combination of policies, which focus on promoting equity, to achieve this bold endgame goal.