People think that the size of a cigarette pack, like how many cigarettes in a pack, is linked to how much people smoke. However, we do not have clear proof that changing the pack size directly causes a change in smoking habits. Even though there is no rule about the biggest size a cigarette pack can be, the tobacco industry is making bigger and bigger packs.
In Australia, the smallest pack has 20 cigarettes, but you can also get packs with up to 50 cigarettes. We wanted to figure out how it would affect smoking if the smallest pack had to have at least 25 cigarettes instead of 20.
We did a study using two steps to see if changing the size of cigarette packs makes a difference. People in Australia who usually buy packs with 25 or more cigarettes were chosen randomly to use either pack with 20 cigarettes (that is the change we wanted to test) or just stick with their regular packs for four weeks.
To find out if it worked, we checked how many cigarettes they smoked each day by looking at all the finished packs they used. We also checked partway through to see if we needed more people in the study to make sure we could see a real difference in the results.
When we checked the data halfway through, we saw that we needed many more people in the study to be sure we could find a clear result. However, getting that many participants was not possible, so we had to stop collecting more data.
Looking at the info we already had from 79 people, we found that those using packs with 20 cigarettes smoked, on average, 15.9 cigarettes a day, while the ones with regular packs smoked 16.8 cigarettes a day. The difference was small, about 0.9 cigarettes less for the ones using the packs with 20 cigarettes.
We are still not sure if making cigarette packs have fewer cigarettes, like going from 25 to 20, actually makes people smoke less. However, what we found does not say it is a bad idea to limit how many cigarettes can be in a pack.
This study had some things that could be done better, and we really need another study that’s more effective to see how big packs affect smoking.