They showed that 20 percent of people trying to quit with the aid of e-cigarettes reported having stopped smoking conventional cigarettes.
That compared with just 10.1 percent of those using over-the-counter aids such as nicotine replacement patches or gum. Of those using willpower alone, 15.4 percent had managed to stop.
E-cigarettes contain nicotine — a stimulant not thought to be particularly harmful, although it is addictive — delivering it in a water vapor rather than in smoke from burning tobacco.
A relatively new product, they have become highly controversial, with public health opinion split over whether they might be a powerful tool in helping those hooked on cigarettes to finally give up, or whether they simply replace one bad habit with another.
Because switching to e-cigarettes from tobacco ones does not entail kicking the addiction to nicotine, some specialists say they could spell the end of smoking — which the World Health Organization (WHO) calls “one of the biggest public health threats the world has ever faced.”
But critics point to a lack of long-term scientific evidence to support the safety and effectiveness of e-cigarettes, and warn they may also renormalize smoking, enticing children or other nonsmokers to take it up.
West agreed that evidence about long-term use of e-cigarettes is scant, but he stressed that the balance of risks had to be weighed against the very strong evidence of tobacco’s harms.
“It’s not clear whether long-term use of e-cigarettes carries health risks, but from what is known about the contents of the vapor, these will be much less than from smoking,” he said.
Smoking tobacco kills half of all those who do it, according to the WHO, and has a death toll of 6 million people a year.
West said evidence shows that smokers who seek professional help from doctors or health clinics that provide stop-smoking services have the highest success rates in quitting.
“These almost triple a smoker’s odds of successfully quitting compared with going it alone or relying on over-the-counter products,” he said.
(Reporting by Kate Kelland; editing by Catherine Evans)