Researchers at the Universities of Bristol and Cambridge wanted to see if 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. 

Following a study with 252 participants in Canada, researchers found that smoking from packs of 20 compared with packs of 25 cigarettes reduced the number of cigarettes smoked per day. 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. 

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. 

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. 

Read the University of Bristol news item

Paper: ‘Cigarette pack size and consumption: a randomised cross-over trial’ by Ilse Lee, Anna K. M. Blackwell, et al. in  Addiction [open access]