Study participants were randomly assigned to receive either text-only warnings or pictorial warnings on their cigarette packages for 4 weeks in total.
Image credit: JAMA
Results of the study are published in JAMA Internal Medicine.
According to the study authors, the United States led the world by being the first to require cigarette pack warnings in 1966. However, since then, the country has fallen behind others in implementing effective pack warnings.
The World Health Organization (WHO) Framework Convention on Tobacco Control is an international treaty that recommends pictorial warnings on cigarette packs.
The U.S., however, has not ratified this treaty.
Interestingly, the 2009 Family Smoking Prevention and Tobacco Control Act requires pictorial warnings, but implementing this act was blocked by a lawsuit led by the tobacco industry in 2012.
The U.S. Court of Appeals for the District of Columbia Circuit subsequently ruled against pictorial warnings proposed by the Food and Drug Administration (FDA), suggesting the FDA had "not provided a shred of evidence" that such warnings reduce smoking.
Because there were gaps in such research, Noel T. Brewer, Ph.D., of the University of North Carolina-Chapel Hill, and colleagues set out to conduct a large randomized clinical trial that examined how adding warning pictures to cigarette packs affected smoking behavior.
'Results could mean substantial benefits for U.S. smokers'
For their study, the researchers used four warning photos illustrating smoking risks that accompanied text required by the Tobacco Control Act.
- Cigarette smoking is responsible for over 480,000 deaths in the U.S. each year
- On average, smokers die 10 years earlier than non-smokers
- Smoking causes cancer, heart disease, stroke, lung disease, diabetes, and COPD.
They also used four text-only warning statements that have been required on cigarette packages since 1985.
In total, 2,149 adult smokers from California and North Carolina were enrolled in the study, and 1,901 completed it. The participants were randomly assigned to receive either text-only warnings or pictorial warnings on the cigarette packages for 4 weeks in total.
The participants then attended weekly follow-up visits, and the researchers conducted surveys at the start of the study and each follow-up visit.
Results showed that the smokers who received pictorial warnings were more likely to try quitting during the trial, compared with those who received text-only warnings.
In detail, 40 percent of smokers who received pictures made a quit attempt, compared with 34 percent in the text-only group. Additionally, 5.7 percent of smokers in the picture group had quit smoking for at least a week by the end of the trial, compared with 3.8 percent of smokers in the text group.
Although this difference may not appear to be significant, the researchers say it "could have a substantial benefit across the population of U.S. smokers."
Findings support requirement for pictorial warnings
The study draws its strengths from a large and diverse sample of smokers who received the warnings on their cigarette packs every day. Furthermore, the researchers say the generalizability of their findings across many different subgroups is promising.
However, they do note some limitations. These include a lack of understanding as to what effects the pictorial warnings may have over a longer time period. Additionally, the researchers note that participant self-selection could have yielded a study population with a greater interest in quitting smoking.
Commenting on their findings, the researchers write:
"Implementation of pictorial cigarette pack warnings in the U.S. is on hiatus. Our trial findings provide timely and important information as the U.S. and other countries consider requiring pictorial cigarette pack warnings."
They add that the WHO recommend pictorial warnings but do not require them. "Our trial findings support strengthening the treaty to require pictorial warnings on cigarette packs," the researchers conclude.
Future studies could benefit from a longer duration, they add.