The first experimental evidence that people smoke more when smoking from larger pack sizes has been published in Addiction today. The research was designed to test whether lowering cigarette pack sizes from 25 to 20 reduced the number of cigarettes smoked.
Smoking remains one of the largest risk factors for disease globally and is a major contributor to the gap in life expectancy and years lived in good health between the richest and poorest groups.
Food studies show that smaller portion and pack sizes reduce how much people eat and reducing glass and bottle sizes can reduce the amount of alcohol that people drink.
The research team, led by Professor Theresa Marteau and Ilse Lee at the University of Cambridge, wanted to see if reducing the size of cigarette packs – the number of cigarettes in a single pack – could help to reduce the number of cigarettes smoked, given smoking fewer cigarettes per day may increase the chances of quitting.
Packs of 20 cigarettes are standard in most countries, including the UK, although larger pack sizes are common in some countries such as Canada and Australia.
The researchers conducted this study in Canada, where cigarette packs of 25 are available. Participants in the study were adults who smoked from pack sizes of 25. They were asked to smoke from two sizes of cigarette packs during the study: packs that either contained 20 or 25 cigarettes.
Each participant smoked from one pack size for 14 days, then had a break, and then smoked from the other pack size for another 14 days. Participants were randomly allocated to the order in which they smoked from the two pack sizes. 240 of the 252 participants recruited (95%) completed the study.
The study was presented to participants as investigating how cigarette pack size influences the effectiveness of health warnings. This was to reduce the chance of participants focusing on their cigarette consumption in relation to pack size.
The results show that smoking from packs of 20 compared with packs of 25 cigarettes reduced the number of cigarettes smoked per day.
Research participants smoked 1.3 fewer cigarettes per day or 7.6% fewer from packs of 20 cigarettes, compared with the packs of 25 cigarettes.
However, most of the participants preferred the larger packs, seeing them as better because they simply contained more cigarettes, they lasted longer or they were better value for money.
The researchers explain that smaller packs might reduce consumption because it takes effort to buy or open a new pack, or because people tend to consume a specific number of units in a pre-specified period of time. For example, people often consume one glass or bottle of wine with dinner, and one pack of cigarettes in a day or during a 2-day period. When the glass, bottle or pack contain more, more is consumed.
Biochemical measures of nicotine were not taken in this study so the team couldn’t assess the extent to which people may have compensated for smoking less cigarettes, perhaps by inhaling more or taking more puffs.
The current study provides the first experimental evidence that people smoke more when smoking from larger pack sizes, raising the question of whether capping pack sizes might be a useful addition to existing tobacco control measures.
Theresa Marteau and Ilse Lee, authors, University of Cambridge
This research was funded by Wellcome.
Read the research
Lee I, Blackewell AKM, Hobson A, Wiggers D, Hammond D, De-loyde K, Pilling MA, Hollands GJ, Munafò MR, Marteau TM. Cigarette pack size and consumption: a randomised cross-over trial. Addiction 2022 Nov 3
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