Tweed EJ, Mackay DF, Boyd KA, Brown A, Byrne T, Conaglen P, Craig P, Demou E, Graham L, Leyland AH, McMeekin N, Pell JP, Sweeting H & Hunt K (2021) Evaluating the health impacts of a national smokefree prisons policy using trends in medication dispensing: an interrupted time series analysis as part of the Tobacco In Prisons study (TIPs). Lancet Public Health.
Internationally, smoking prevalence among people in custody (PiC) is high. In response, some jurisdictions have introduced smokefree prison policies, but evidence on their health impacts is limited. In Scotland, all prisons implemented a comprehensive smokefree policy in 2018 following a 16-month anticipatory period. We used data on medication dispensing to evaluate the impact of this policy on cessation support, health outcomes, and potential unintended consequences among PiC.
Using data from 44,660 individuals across 14 closed prisons between 30/03/2014 and 30/11/2019, we estimated changes in dispensing rates associated with policy announcement (17/07/2017) and full implementation (30/11/2018) using seasonal
autoregressive integrated moving average models. Medication categories of primary interest comprised treatments for: nicotine dependence (as an indicator of smoking cessation/abstinence attempts)); acute smoking-related illnesses(short-acting
bronchodilators and antibiotics; glyceryl trinitrate; gastro-oesophageal reflux treatments; anti-bacterial eye preparations); and mental health (antidepressants). We included anti-epileptic medications, which should be unaffected by the policy, as a
There was a 44% step increase in dispensing of treatments for nicotine dependence at implementation (2,249 items per 1,000 PiC per fortnight, 95% CI 1,875 to 2,624). Dispensing for smoking-related illnesses showed a 9% step decrease at implementation, largely accounted for by respiratory medications (-646 items per 1,000 PiC per fortnight, 95% CI -1,111 to -181). No changes associated with announcement or implementation were observed for mental health dispensing or the control series.
Smokefree prison policies may improve respiratory health among PiC and encourage smoking abstinence/cessation without apparent short-term adverse effects on mental health.
National Institute of Health Research Public Health Research programme; Chief Scientist Office (UK); Medical Research Council (UK).
Output Status: Forthcoming
Lancet Public Health