British health officials said Wednesday that e-cigarettes are about 95 percent less harmful than smoking and added that they do not serve as a gateway or "route into smoking for children or non-smokers."

"E-cigarettes are not completely risk free but when compared to smoking, evidence shows they carry just a fraction of the harm. The problem is people increasingly think they are at least as harmful and this may be keeping millions of smokers from quitting. Local stop smoking services should look to support e-cigarette users in their journey to quitting completely," said Kevin Fenton, director of Health and Wellbeing at Public Health England.

There's plenty of competing literature about the hot-button issue as vaping, or using e-cigarettes, has been growing in popularity across the globe.

The study—which e-cigarette advocates suggested should go a long way in preventing harsh regulations in the UK and getting them instead used to help smokers quit—contradicts a 2014 report by the World Health Organization. The WHO report called for major regulation of e-cigarettes as well as a ban on their use indoors and sales to minors. What's more, University of Southern California researchers announced days ago that teens in the US who use electronic cigarettes have a strong possibility of using regular cigarettes.

The UK decision comes as US health officials are moving to regulate e-cigarettes.

The Food and Drug Administration is considering adding warning labels on the liquid nicotine used in electronic devices and is also mulling a requirement for the liquid to be sold in child-resistant packaging.

"The continuing rise in popularity of electronic nicotine devices (ENDS), such as e-cigarettes, which often use liquid nicotine and nicotine-containing e-liquids, has coincided with an increase in calls to poison control centers and visits to emergency rooms related to liquid nicotine poisoning and other nicotine exposure risks," the US agency announced in July.

There are a variety of e-cigarette styles. One type has a powered atomizer that is activated upon inhalation. Other types use a heating coil that is switched on by the user. In all the devices, liquid nicotine or other products in a cartridge are heated, become vapor, and are inhaled. Nicotine content varies by product and maker.

"E-cigarettes could be a game-changer in public health in particular by reducing the enormous health inequalities caused by smoking," Professor Ann McNeil, who helped author the study, said. She added that "e-cigarettes are another tool for stopping smoking and in my view smokers should try vaping, and vapers should stop smoking entirely."