'More research' needed into safety of electronic cigarettes
The need for more research into the long-term health effects of electronic cigarettes has been highlighted by scientists in the British Medical Journal.
Andreas Flouris and Dimitris Oikonomou, from the Institute of Human Performance and Rehabilitation in Greece, are concerned that not enough research has been carried out into the safety - or otherwise - of so-called 'e-cigarettes'.
Their position has been endorsed by Cancer Research UK, which is also concerned by the current lack of information.
E-cigarettes are battery-powered devices that simulate cigarettes by allowing the user to inhale a nicotine vapour.
Sales of the devices are thought to be increasing and a number of celebrities - including Kate Moss and Leonardo DiCaprio - have been spotted using them.
However, few studies have been conducted into the health effects of smoking e-cigarettes and those that have been published have reached differing conclusions.
One, carried out by the US Food and Drug Administration (FDA), found that the amount of nicotine provided with each puff often varies from the amount stated on the label, prompting the agency to express concern about e-cigarettes.
In contrast, a private enterprise called Health New Zealand (HNZ) found that the labelling on e-cigarettes reflected their actual nicotine content.
The FDA's research also detected the presence of diethylene glycol - a highly toxic liquid - in one of the cartridges it investigated, while both the FDA and HNZ found cancer-causing chemicals called tobacco specific N-nitrosamines.
In its report, the FDA suggested that e-cigarettes may therefore be harmful, but HNZ recommended their use as they are likely to be less dangerous than tobacco products.
Meanwhile, a Greek organisation called Demokritos has maintained a neutral stance on the subject after conducting its own research.
Drs Flouris and Oikonomou note that this "represents all the knowledge we currently have about e-cigarettes" and that the European Centre for Disease Prevention and Control is yet to publish any research on the subject.