Smoking fewer cigarettes per day can increase the chances of success in quitting smoking. Reducing the number of cigarettes in a pack could be a promising policy change, but the causal effect of this change is not yet known. In this study, the researchers hypothesized that reducing the number of cigarettes in a pack from 25 to 20 cigarettes would help reduce the number of cigarettes consumed per day.
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In this randomized controlled and crossover study, two intervention periods of 14 days each were included, with a seven-day rest period between them. The subjects themselves purchased the cigarettes we smoked in the study. The researchers instructed the subjects to smoke cigarettes of their preferred brand from packs of 25 or 20 cigarettes during each of the 14-day intervention periods, according to random assignment.
Adult subjects who were used to smoking cigarettes from packs containing 25 cigarettes each participated in the study. The subjects were recruited between the dates July 2020-June 2021. Of the 252 subjects randomly assigned to the study, 240 (95%) completed the study and 236 (94%) provided sufficient information for initial data analysis. The main outcome tested was the number of cigarettes the subjects smoked each day.
The results of the study demonstrated that when the subjects used packs of 20 cigarettes they smoked fewer cigarettes per day (n=234, an average of 15.7±7.1 cigarettes per day), compared to when they used packs of 25 cigarettes (n=235, an average of 16.9±7.1 cigarettes per day) ). After adjusting for pre-defined variables (number of cigarettes smoked initially and smoking intensity), the models hypothesized that when the subjects used packs of 20 cigarettes they smoked 1.3 fewer cigarettes per day (95% confidence interval, 95% confidence interval, -1.7 and -0.9), which is equivalent to a reduction of 7.6% (95% confidence interval, -10.1 to -5.2) in the amount of cigarettes consumed per day.
The researchers’ conclusion was that using packs of 20 cigarettes, compared to using packs of 25 cigarettes, caused a reduction in the number of cigarettes consumed each day.
source:
Lee I, Blackwell AKM, Hobson A, Wiggers D, Hammond D, De-Loyde K, Pilling MA, Hollands GJ, Munafò MR, Marteau TM. Cigarette pack size and consumption: a randomized cross-over trial. Addiction. 2023 Mar;118(3):489-499. doi: 10.1111/add.16062. Epub 2022 Nov 3. PMID: 36326156.