GREEK researchers called recently for more safety studies into electronic cigarettes, saying scientific knowledge of them was â€œvery limitedâ€.
Electronic cigarettes, or e-cigarettes, were first made in China and are sold mostly on the Internet.
They are battery-powered devices which emit a â€œpuffâ€ or fine mist of nicotine into the lungs and are intended to replace normal cigarettes and help smokers quit.
The products are at the centre of a legal battle in the United States between manufacturers and the Food and Drug Administration (FDA), which regulates drugs and which wants to stop e-cigarettes from being imported into the U.S
The FDA, which conducted research into e-cigarettes, has expressed concerns about their safety, and teams from Greece and New Zealand have also carried out studies into them.
But interpretations of the three reports vary, with the New Zealand study saying e-cigarettes should be recommended because they are safer than tobacco cigarettes, and the Greek study taking a broadly neutral stance.
â€œThe limited information given in these three reports represents all the knowledge we currently have about e-cigarettes,â€ Andreas Flouris and Dimitris Oikonomou, of the Institute of Human Performance and Rehabilitation in Greece, wrote in the British Medical Journal.
â€œThis may be one reason why the battle.between the FDA and e-cigarette manufacturers has been so heated.â€
A U.S judge last week granted an injunction barring the Obama administration from trying to ban imports of e-cigarettes, saying the move was part of â€œaggressive effortsâ€ by the FDA to regulate â€œrecreational tobacco products.â€
Tobacco is the leading preventable cause of death in the world, killing more than 5 million people a year. A report by the World Lung Foundation last August said smoking could kill a billion people this century if trends hold.
Flouris and Oikonomou said that while â€œalternative smoking strategies are always welcome in an effort to reduce the threat to public healthâ€ caused by tobacco, safety was also vital.
â€œMore rigorous chemical analyses are needed, followed by extensive research involving animal studies and, finally, clinical trials in humans,â€ they wrote.
Scientists want more safety studies on e-cigarettes