Researchers find e-cigs less addictive than cigarettes

The popularity of e-cigarettes, which typically deliver nicotine, propylene glycol, glycerin and flavourings through inhaled vapour, has increased in the last five years.

Jonathan Foulds from the Pennsylvania State University College of Medicine said e-cigs contain far fewer cancer-causing and other toxic substances than cigarettes but their long-term effects on health and nicotine dependence are unknown.

To study e-cigarette dependence, researchers developed an online survey including questions designed to assess previous dependence on cigarettes and almost identical questions to assess current dependence on e-cigs.

Higher nicotine concentration in e-cig liquid and use of advanced second-generation e-cigs which deliver nicotine more efficiently than earlier "cigalikes" predicted dependence.

Consumers who had used e-cigs longer also appeared to be more addicted.

"However, people with all the characteristics of a more dependent e-cig user still had a lower e-cig dependence score than their cigarette dependence score," Foulds said.

"We think this is because they're getting less nicotine from the e-cigs than they were getting from cigarettes.

"It has the potential to do good and help a lot of people quit, but it also has the potential to do harm. Continuing to smoke and use e-cigs may not reduce health risks. Kids who have never smoked might begin nicotine addiction with e-cigs," Foulds said.

The findings also have implications for developing e-cigs to help people quit smoking.

"We might actually need e-cigarettes that are better at delivering nicotine because that's what is more likely to help people quit," Foulds said.