In a statement published in the European Respiratory Journal, a coalition of respiratory doctors and scientists from six continents have warned of the dangers posed to children and adolescents by electronic cigarettes .
They say there is mounting evidence that e-cigarettes damage health and are highly addictive, yet manufacturers are marketing them as "healthier" cigarettes and their popularity among young people is growing.
As a result, they are calling for an immediate ban on flavourings and on marketing e-cigarettes as lower risk alternatives to children and adolescents.
The Forum of International Respiratory Societies  is a collaborative of nine organisations from North and South America, Europe, Africa, Asia and Australia that was created to promote lung health worldwide.
The paper brings together a wide range of research findings on e-cigarettes. It highlights evidence that children and adolescents are highly susceptible to nicotine addiction, and that use of e-cigarettes has risen steeply in this age group to become the most commonly used tobacco-related product among adolescents in some countries.
The authors lay out a set of evidence-based recommendations for protecting youth from nicotine addiction and its harmful effects.
The paper was co-authored by Thomas Ferkol MD, Alexis Hartmann professor of paediatrics and professor of cell biology and physiology at Washington University in St. Louis, USA. He said: "Until recently, the risks of e-cigarettes and their rising popularity with children and adolescents were under-recognised or ignored. We wrote this statement to address growing public health concerns over e-cigarette use among youths.
"Product design, flavours, marketing, and perception of safety and acceptability have increased the appeal of e-cigarettes to young people. These products are 'normalising' smoking and leading to new generations addicted to nicotine."
The authors found growing evidence that e-cigarettes act as a "one-way bridge" to cigarette smoking in adolescents.
Professor Ferkol added: "Some people truly believe e-cigarettes could be used as a smoking cessation technique, but these products also are an entry to nicotine addiction and tobacco use in young people."
Charlotta Pisinger, clinical professor of tobacco control at Bispebjerg and Frederiksberg Hospital and University of Copenhagen, Denmark was also a co-author. She said: "Although exposure to potentially harmful ingredients from electronic cigarettes may be lower than traditional cigarettes, this does not mean that e-cigarettes are harmless.
"And when we're talking about children and adolescents who are trying e-cigarettes for the first time, we should not be comparing their use to traditional cigarettes. We should be comparing them to no tobacco use."
The paper puts forward a series of expert recommendations that the authors say will protect this vulnerable group. They state that e-cigarettes should be regulated in the same way as tobacco products and included in smoke-free policies. They say that there should be a ban on sales to youths worldwide, which must be enforced. Advertising e-cigarettes as lower-risk alternatives directed to youths and young adults should cease.
The paper also calls for a ban on flavoured products, because there is evidence that flavourings draw young people to e-cigarettes. There are currently more than 7,500 different flavoured e-cigarettes and refills available. Finally, the authors recommended further research on the health effects of e-cigarettes as well as surveillance of use across different countries.
Regulation of e-cigarettes varies widely around the world. For example, legislation on a minimum age for buying e-cigarettes is non-existent or not enforced in most countries.
Dr Aneesa Vanker, a senior specialist in paediatric pulmonology, at the Red Cross War Memorial Children's Hospital, University of Cape Town, South Africa, was also a co-author the paper. She added: "E-cigarettes are largely unregulated, particularly in low and middle-income countries. They are marketed as a smoking cessation tool and a safer alternative to tobacco cigarettes.
"However, there is growing evidence that nicotine has many acute and long-term adverse effects, including addiction. Young people are at particular risk for this.
"We want local, national, and regional decision-makers to recognise the growing public health threat that e-cigarettes pose to children and adolescents. Inhaling something other than air is never good for a child's lungs."