Purchasing of tobacco-related and e-cigarette-related products within prisons before and after implementation of smoke-free prison policy: analysis of prisoner spend data across Scotland, UK

Abstract

Objectives To examine the effect of smoke-free prison policy implementation in November 2018 on purchasing patterns in the prison canteen (shop). Design Interrupted time series. Setting All 12 closed, publicly run prisons in Scotland, UK. Participants People in custody (PiC) between August 2018 and end of March 2019 (n=11 944). Interventions Implementation of smoke-free prisons policy. Outcome measures Total spent on all products, nicotine-related products, and food and beverage products per week. Methods Canteen data were provided for the period July 2018–September 2019 by the Scottish Prison Service. In a series of generalised linear mixed effects models, the amount spent before and after implementation of smoke-free prison policy was compared for all purchases in the time period, and for PiC identified as ‘smokers’ and ‘non-smokers’ from their pre-implementation tobacco purchasing patterns. Results The amount spent on nicotine-related products significantly decreased from pre-implementation to post implementation (incident rate ratio (IRR) 0.40; 99% CI 0.33 to 0.51, p