Smoking warnings have to be really really big to be effective.

A couple months ago we posted a number of very disturbing cigarette warning labels from around the world and wondered whether perhaps a picture of a rotting, stinking, bleeding tumor on a guys throat would perhaps help lower the incidence of smoking. In the March issue of the American Journal of Preventative Medicine researchers have taken a step toward showing big obnoxious warnings are the best.

The abstract does a good job describing the study so I'll let them do it:

Text and Graphic Warnings on Cigarette Packages: Findings from the International Tobacco Control Four Country Study

David Hammond, PhDaCorresponding Author Informationemail address, Geoffrey T. Fong, PhDb, Ron Borland, PhDc, K. Michael Cummings, PhDd, Ann McNeill, PhDe, Pete Driezen, MSca

Background

Health warnings on cigarette packages provide smokers with universal access to information on the risks of smoking. However, warnings vary considerably among countries, ranging from graphic depictions of disease on Canadian packages to obscure text warnings in the United States. The current study examined the effectiveness of health warnings on cigarette packages in four countries.
Methods

Quasi-experimental design. Telephone surveys were conducted with representative cohorts of adult smokers (n=14,975): Canada (n=3687), United States (n=4273), UK (n=3634), and Australia (n=3381). Surveys were conducted between 2002 and 2005, before and at three time points following implementation of new package warnings in the UK.
Results

At Wave 1, Canadian smokers reported the highest levels of awareness and impact for health warnings among the four countries, followed by Australian smokers. Following the implementation of new UK warnings at Wave 2, UK smokers reported greater levels of awareness and impact, although Canadian smokers continued to report higher levels of impact after adjusting for the implementation date. U.S. smokers reported the lowest levels of effectiveness for almost every measure recorded at each survey wave.
Conclusions

Large, comprehensive warnings on cigarette packages are more likely to be noticed and rated as effective by smokers. Changes in health warnings are also associated with increased effectiveness. Health warnings on U.S. packages, which were last updated in 1984, were associated with the least effectiveness.

Of course this study has only shown that people notice the big honking ads more - but hopefully the next study will show people are smoking less because of this newly noticed knowledge.

And in case you need to be grossed out a little more here's some more warning labels from around the world ;)