Something as simple as the color of a cigarette packet can dupe smokers into thinking the cigarettes inside are less dangerous to their health, a study showed.
The study, conducted by researchers at the University of Waterloo in Canada showed that, in addition to words like "light," "mild," and "low-tar," which have been banished from cigarette packets in more than 40 countries, design elements and color are being used by tobacco companies to lull smokers into a false sense of security about the harmful effects of smoking.
"Substantial proportions of adults in the study associated perceptions of risk and tar delivery with package design," the study's authors wrote.
The packets were made to look and feel as if they were real and contained cigarettes, but the brand names were made up, to avoid "contamination."
Each packet carried a pictorial health warning, as required under Canadian law.
The pairs of cigarette packets that were presented to participants in the study were identical, except for one element: either a term such as "full flavor" or "light," or a design element on the packet, such as the color, were different.
The researchers found that around 80 percent of participants in the study believed that cigarettes in a light blue packet would deliver less tar, have a smoother taste and pose less of a danger to health than those in darker blue packaging.
Seventy percent of study participants said a packet with a white symbol would deliver less tar, be smoother and less unhealthy than cigarettes in a packet with a grey symbol.
And an equal number -- seven in 10 -- believed the same benefits to be true of cigarettes in a packet bearing the words "charcoal filter" and showing an image of the filter.
Smokers were more likely than non-smokers to be duped by the imagery, words and color of a cigarette package because "they have greater incentive to believe that some cigarettes may be less harmful," the study found.
According to the study, tobacco use is responsible for one in 10 deaths around the world and is the leading cause of preventable deaths.
With the tobacco industry recognizing "rising levels of health concern" as a key threat to its existence, it has made reassuring consumers about the risks associated with smoking "an important function of tobacco marketing," the study said.
"A central feature of this marketing strategy has been to promote the perception that some cigarettes are less hazardous than others," wrote David Hammond and Carla Parkinson, the authors of the study.
The pair said tobacco packaging "has served as a critical medium for shaping perceptions of consumer risk."
Forty-four countries, including the United States, have banned the use of the words "light," "mild," and "low-tar," on cigarette packages, saying they mislead consumers about the health risks of smoking, the study says.
The authors want the list of prohibited words to be expanded and for cigarettes to be sold in plain packaging to try to stop the tobacco industry misleading smokers.
"There is growing evidence that the removal of brand imagery from packaging -- so-called 'plain' packaging -- reduces the appeal of brands and increases the salience of health warnings," the study says.
"Research to date suggests that plain packages are less attractive and engaging and may reduce brand appeal, particularly among youth."
The study was published in the Oxford University Press Journal of Public Health.