Image copyright Getty Images Image caption Almost three million people use e-cigarettes in the UK

E-cigarettes are "definitely" less harmful than smoking tobacco, health bodies in Scotland have stated for the first time.

NHS Health Scotland said it wanted to "clarify" confusion around the harms and benefits of vaping devices.

More than 20 organisations have signed up to the consensus, which was led by NHS Health Scotland.

But health chiefs said that using e-cigarettes while still smoking did not provide any health benefits.

The consensus statement, published by Scotland's national health education and promotion agency, was agreed by the Scottish government, health boards, academia and charities such as the British Lung Foundation and Cancer Research UK.

There are estimated to be about 2.9 million people in the UK who use e-cigarettes. More than half of them have given up smoking tobacco, a recent study has suggested.

Other research for Public Health England concluded that e-cigarettes were 95% less harmful than normal cigarettes.

However, about nine million people still smoke in the UK despite the rise in e-cigarette use since 2012.

Image copyright Getty Images Image caption Many people use vaping to help them give up smoking tobacco, studies have found

Dr Andrew Fraser, director of public health science at NHS Health Scotland, told BBC Scotland: "E-cigarettes have been around for a number of years now and we are learning more and more about them but I think it is safe to say that they are a lot safer than cigarettes.

"If we are trying to help people make a decision about giving up smoking tobacco then e-cigarettes are a good option to consider."

Dr Fraser said vaping was not available on NHS prescription, unlike some other treatments, but it was an option for those trying to give up smoking cigarettes.

"We would encourage people to consider them and we would encourage people providing smoking cessation serves to offer them as an option to people who are willing to pay for them," he said.

Image caption Dr Fraser said vaping was definitely safer than smoking tobacco

Dr Fraser said he wanted to deliver a "positive" message for e-cigs, saying they "weren't anything like as dangerous as cigarettes".

He said there had been reports that likened the risk of vaping to smoking tobacco but this was not the case.

However, he added that e-cigarettes were not risk free.

"They contain nicotine, which is addictive in itself, and they contain and a number of other combustible materials," Dr Fraser said.

"But if you take it all in the round and compare it with the alternative they are a lot less harmful than cigarettes."

He added that ideally vaping would be used a way to give up smoking entirely and he advised against "double running" - taking both tobacco and e-cigarettes.

Last year, Scotland's largest health board ruled that e-cigarettes could be used within the grounds of its hospitals.

NHS Greater Glasgow and Clyde decided to allow restricted use of the devices after new evidence that they helped tackle tobacco smoking.

Tobacco smoking was banned across all health grounds in Scotland in April 2015, but health boards were given discretion over the use of vaping devices outside buildings.

Cancer chemicals

Sheila Duffy, chief executive of Ash Scotland, a charity aiming to reduce the harm caused by tobacco, said the joint statement on e-cigarettes brought "clarity" to the issue.

"There is now agreement that vaping e-cigarettes carries less risk than smoking tobacco," she said.

"Although we still don't know the long-term health effects of vaping, we can be confident that any smoker switching entirely to e-cigarettes will be taking in far fewer cancer-causing chemicals.

"Tobacco is lethal and I'd encourage anyone who smokes to find a way of quitting that works for them, which could include using e-cigarettes, and to make use of the free NHS stop-smoking support available to help."