Wednesday, 18 August 2021

Randomised controlled trial shows that plain packaging doesn't work

Nearly a decade after plain packaging was introduced in Australia, a randomised controlled trial has been conducted to see if the policy actually works. The trial was registered last September and its results were published last week.

You probably missed it. It received virtually no media coverage, for reasons that will soon become obvious, and it was confusingly portrayed as being a study of graphic warnings. Indeed, the study is titled 'Effect of Graphic Warning Labels on Cigarette Packs on US Smokers’ Cognitions and Smoking Behavior After 3 Months'.

The researchers gathered a group of 357 smokers and split them into three groups. Participants were sold cigarettes for four months (online delivery). In the first month they were sold cigarettes in a regular, US pack with no graphic warnings and a relatively discreet written warning. Thereafter they were sold cigarettes either in a regular US pack, a totally blank pack or a pack with graphic warnings on them. 

It is only at the end of the study that it becomes clear that the pack with graphic warnings is actually what we know as a plain pack. In fact, they literally used plain packs from Australia.

In this study, we chose the Australian standardized packaging for our GWL packs rather than the hybrid packs proposed for implementation in the US.

These are shown in one of the appendices:

During the course of the study, the researchers sent participants two text messages a day asking if they agreed with various statements (such as "my last cigarette was satisfying") and asking how many cigarettes they had smoked in the last four hours. They also sent them a weekly survey asking questions such as "How often did you think about wanting to quit?"

The participants also took part in two detailed surveys during the course of the study and were tested for cotinine to confirm their smoking status.

So what happened? In line with several other studies, smokers exposed to the graphic warnings had a slightly less positive perception of cigarettes. They also expressed a "marginal increase" in health concerns and declared themselves to be slightly more interested in quitting.

But this didn't lead to any behavioural changes. They didn't quit. They didn't reduce the number of cigarettes they smoked. They weren't more likely to manage even four hours without a cigarette.  

Across the first 2 months of the intervention, only those in the GWL [graphic warning labels] pack group reported a consistent decrease in their positive perceptions of the cigarettes that they smoked, although the expected increase in perceived health concerns was not significant. Although there was a significant increase in cognitions about quitting in the GWL group, there was no evidence of increased quitting or reduced consumption, and this was biochemically validated at the postintervention visit.

This seems to have come as a surprise to the authors.

Health concerns increased in all study groups during the intervention, with only a marginal increase in the GWL pack group. As the theory supporting mandated GWLs expects that their effect will be achieved through increased health concerns, this lack of a marked between-group difference was unexpected. 

.. Although the GWL group participants were more likely to think about quitting during the study intervention, there was no evidence of increased quitting behavior. Our measure of at least 1 weekly 4-hour smoking abstinence was designed to maximize the possibility of identifying early quitting activity. What was surprising is that the GWL group participants, who were more likely to think about quitting, were not much more likely to report these short smoking abstinences or to report lower daily cigarette consumption. 

If they were surprised, they shouldn't have been. Because...

Our study is in line with previous research indicating that intentions to change are rarely sufficient to achieve change in an addictive behavior.

So why don't graphic warnings work?

That the GWL pack did not experience a significant increase these cognitions may reflect the high level of awareness of the health consequences of smoking

Indeed. Smokers are well aware of the risks, as are nonsmokers who take up the habit. If anything, they have an exaggerated perception of the risks. We have had evidence for over a decade telling us that hammering home the risks with graphic warnings makes no difference to smoking rates regardless of what smokers might tell researchers in focus groups.   

The campaigns for both graphic warnings and plain packaging were driven by studies showing that people expressed certain views when confronted with the new packs. Often these boiled down to little more than them saying that they found an ugly pack ugly and an attractive pack attractive. At other times, they expressed a vague desire to stop smoking. 

But talk is cheap and subjective evidence in the field of tobacco control is riddled with social desirability bias. Stated preferences are worthless if they are not accompanied by action. This study was explicitly "designed to maximize the possibility of identifying early quitting activity". The researchers would have settled for four hours abstinence, but the participants couldn't even manage that.

The authors of the study, who are based in California, attempt to salvage something from it by talking up the impact of graphic warnings on "positive perceptions of cigarettes" and by speculating that these packs could be effective if combined with other (unspecified) policies, but the results speak for themselves.

There is a huge difference between a standard American cigarette pack with a modest health warning and a standardised Australian cigarette pack with no branding whatsoever and a large graphic warning. And yet abruptly switching from one to the other made essentially no difference to smokers' behaviour.

This randomised controlled trial shows that graphic warnings are essentially useless, but it also shows that plain packaging doesn't work. Two birds, one stone. The use of a totally blank cigarette pack as a third option in the study helps to underline how futile the branding ban aspect of plain packaging is. Removing the branding didn't even change perceptions, let alone behaviour.

Tobacco branding on a cigarette pack typically increases a smoker’s perceptions of satisfaction, craving relief, and taste of cigarettes. However, in this study, removal of tobacco branding on the blank pack was not sufficient to decrease these positive perceptions.

It seems a shame that nobody bothered to conduct research like this before governments around the world committed themselves to a policy that doesn't work. But actually they did. A smaller RCT conducted in Britain in 2015 came to much the same conclusion: smokers don't particularly like plain packaging but it doesn't have any effect on their smoking habits. 

The British government went ahead with the policy anyway.

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