What’s in a number? The relationship between the size of a cigarette pack and cigarette consumption

The Dutch government is continually working on policies around tobacco consumption in the Netherlands to reduce smoking. For instance, cigarette packs must have plain packaging and cannot be displayed in stores (other than specialist tobacco stores). Instead, they must be discreetly stored in drawers or cupboards. More recently, new initiatives were announced, including further increases in cigarette prices and the excise duty on tobacco, and the gradual cessation of cigarette sales at supermarkets. However, one attribute not yet directly addressed is the size of cigarette packs being sold in the country. A recent study conducted in Canada sheds light on the importance of cigarette pack size for smoking behaviour. We will unpack their research findings in this sci-fly.   CORE Lee and colleagues (2022) conducted an experiment in Canada to test whether the size of cigarette packs influences subsequent cigarette consumption. They found that smaller cigarette packs are linked to reduced smoking at least in the short term. Their research provides important insight for smoking reduction policy in the public health sector, and for practitioners working with smoking populations motivated to quit smoking. In the EU, cigarette packs have a minimum size of 20 cigarettes to make them expensive and out of reach for younger populations. At the same time, other countries have capped the maximum number of cigarettes per pack at 20. The study by Lee and colleagues indicates that regulations on cigarette pack sizes should be further deliberated to determine the ideal standard to reduce smoking globally.   RESEARCH METHODS WHAT? The goal of the research was to test whether the size of a cigarette pack  – i.e., how many cigarettes it contained – affected how much participants smoked. WHO? The target population was Canadian adults who smoked heavily, that is, at least 10 cigarettes daily. Additionally, they typically purchased factory-made cigarettes in packs of 25 of a brand available in packs of 20 (size a) and 25 (size b). Ultimately, 252 individuals participated in this 5-week-long study. HOW? The researchers used a randomized crossover design, where participants took part in both conditions (packs of 20 cigarettes and 25 cigarettes) so the researchers could compare data of the same individuals. Importantly, whether participants smoked packs of size a or size b first was randomly determined at the start of the study. Phase 1: In the first two weeks, participants smoked cigarettes from their preferred brand in any one size, a or b. Phase 2: In the third week, participants had a “usual” smoking week where they could smoke any brand in any size. Phase 3: In the last two weeks, participants were again asked to smoke cigarettes from their preferred brand. However, this time they only smoked from packs of the other size, b or a. Thus, if participants smoked from packs of 20 in phase 1, they smoked from packs of 25 in phase 3, and vice versa. At the end of each of the 5 weeks, participants sent labelled pictures of the cigarette packs that they (partially) finished in the last week. These photographs were used to calculate how many cigarettes they smoked daily on average in each phase of the study.   FINDINGS When participants smoked only from packs of 20 cigarettes, they smoked 1.3 fewer cigarettes daily and 9 fewer cigarettes per week than when they smoked only from packs of 25. This outcome implies that smaller cigarette packs can reduce cigarette consumption and is an important insight for policymakers in public health.   DETAILS Lee, I., Blackwell, A. K. M., Hobson, A., Wiggers, D., Hammond, D., De‐loyde, K., Pilling, M. A., Hollands, G. J., Munafò, M. R., & Marteau, T. M. (2022). Cigarette pack size and consumption: a randomized cross‐over trial. Addiction. https://doi.org/10.1111/add.16062 Netherlands Enterprise Agency, RVO. (2022, September 27). Sales of tobacco. business.gov.nl. https://business.gov.nl/regulation/sales-tobacco/ van Schalkwyk, M. C. I., McKee, M., Been, J. V., Millett, C., & Filippidis, F. T. (2020). Size matters: An analysis of cigarette pack sizes across 23 European Union countries using Euromonitor data, 2006 to 2017. PLOS ONE, 15(8), e0237513. https://doi.org/10.1371/journal.pone.0237513 This sci-fly was written by Suhaavi Kochhar (Radboud University) for RAD-blog, the blog about smoking, alcohol, drugs and diet.