Smoking has a number of unwanted health effects. Smokers, for instance, are known to die much earlier than their counterparts who do not smoke. Smoking is also associated with a number of fatal diseases including cardiovascular illnesses and cancer.

If you're a smoker and you want to live healthier and longer, it will be to your best interest to stop smoking as early as you can but if you're thinking of using e-cigarettes so it will be much easier to stop smoking, you might as well look for more effective ways that can help ease the difficulty of saying goodbye to cigarettes.

In the research letter "A Longitudinal Analysis of Electronic Cigarette Use and Smoking Cessation" published in the JAMA Internal Medicine March 24, researchers from the University of California in San Francisco surveyed 949 smokers about their smoking habits. One year later, they found that 13.5 percent of the subjects have quit smoking but only nine of the 88 smokers who used e-cigarettes quit.

 "Although electronic cigarettes (e-cigarettes or electronic nicotine delivery systems) are aggressively promoted as smoking cessation aids, studies of their effectiveness for cessation have been unconvincing," the researchers wrote.

The researchers said the study shows proof that e-cigarettes can't make people quit smoking and that smokers who use e-cigarettes do not have increased chances of quitting smoking than smokers who do not use the device.

"There was no association between having tried an e-cigarette and quitting smoking at one-year follow up," study author Rachel Grana said, from the Center for Tobacco Control Research and Education of the University of California, San Francisco. "Because e-cigarettes are unregulated, consumers do not know what they are putting into their bodies and there have been no long-term studies of the health effects."

The researchers, however, admitted of the limitations of their study. They said that the small number of smokers involved in the study could have affected their ability to find a link between e-cigarettes and quitting smoking and they failed to take account the users' characteristics of use such as the frequency and motivation.

Still, they suggested that regulators prohibit the advertising of e-cigarettes as something that can help people to quit smoking until scientific evidence establishes this.

"Regulations should prohibit advertising, claiming or suggesting that e-cigarettes are effective smoking cessation devices until claims are supported by scientific evidence," Grana and colleagues wrote.