Proponents of electronic cigarettes often claim that electronic cigarettes deliver the experience of smoking while eliminating the smell and health risks associated with tobacco smoke.The base liquids - which include propylene glycol (PG), vegetable glycerin (VG), and sometimes polyethylene glycol 400 (PEG400) - have been widely used as a food additive, as a base solution for personal care products such as toothpaste, and in medical devices such as asthma inhalers. However, the health effects of inhaling nicotine vapour into lungs are a subject of uncertainty.
The fact that e-cigarettes may resemble real tobacco cigarettes has been noted by both supporters and detractors. While e-cigarettes may give nicotine addicts more or less the same amount of nicotine as a conventional cigarette, they do not produce the same toxic smoke that can cause lung disease and cancer when inhaled over time. Since there are no products of combustion to be inhaled, no tobacco toxins are inhaled besides nicotine.
World Health Organization
The World Health Organization stated in September 2008 that no rigorous, peer-reviewed studies have been conducted showing that the electronic cigarette is a safe and effective nicotine replacement therapy. WHO does not discount the possibility that the electronic cigarette could be useful as a smoking cessation aid, but insisted that claims that electronic cigarettes can help smokers quit need to be backed up by clinical studies and toxicity analyses and operate within the proper regulatory framework.
Food and Drug Administration
In May 2009, the US Food and Drug Administration (USFDA) Division of Pharmaceutical Analysis tested 19 varieties of electronic cigarette cartridges produced by two vendors NJOY and Smoking Everywhere. Diethylene glycol, a poisonous and hygroscopic liquid, was detected in one of the cartridges manufactured by Smoking Everywhere .Tobacco-specific nitrosamines (TSNAs), known cancer-causing agents, were detected in all of the cartridges from one brand and two of the cartridges from the other brand. Nicotine can also be traced in some claimed nicotine-free cartridges. Further concerns were raised over inconsistent amounts of nicotine delivered when drawing on the device.In some e-cigarettes, "Tobacco-specific impurities suspected of being harmful to humans—anabasine, myosmine, and ß-nicotyrine—were detected in a majority of the samples tested." None of these chemicals, however, were detectable in exhaled vapour.
In July 2009, the FDA publicly discouraged the use of electronic cigarettes and raised concerns that electronic cigarettes may be marketed to young people and lack appropriate health warnings.
The Electronic Cigarette Association criticized the FDA testing as too "narrow to reach any valid and reliable conclusions."Exponent, Inc., commissioned by NJOY to review the FDA's study in July 2009, objected to the FDA analysis of electronic cigarettes lacking comparisons to other FDA-approved nicotine replacement therapy products where similar levels of TSNA were detected. Exponent concluded that the FDA's study did not support the claims of potential adverse health effects from the use of electronic cigarettes.
Furthermore, FDA methods "have been lambasted in journals" by some medical and health research experts who noted that potentially harmful chemicals were measured at "about one million times lower concentrations than are conceivably related to human health."
Additionally, The Tobacco Products Scientific Advisory Committee of the FDA is alleged to have several members who maintain consulting relationships with various pharmaceutical companies who manufacture smoking cessation products. If these allegations are true, this might represent a potential conflict of interest.
American Association of Public Health Physicians
As of April 2010, The American Association of Public Health Physicians (AAPHP) supports electronic cigarettes sales to adults "because the possibility exists to save the lives of four million of the eight million current adult American smokers who will otherwise die of a tobacco-related illness over the next twenty years." However, the AAPHP is against sales to minors.The AAPHP recommends that the FDA reclassify the electronic cigarette as a tobacco product (as opposed to a drug/device combination).
Boston University School of Public Health study
A study by researchers at the Boston University School of Public Health in 2010 concluded that electronic cigarettes were safer than real cigarettes and may aid in breaking the habit of smoking. Researchers said that while further studies on electronic cigarettes were needed, "few, if any, chemicals at levels detected in electronic cigarettes raise serious health concerns." Electronic cigarettes were found to be "much safer" than traditional tobacco ones, and had a level of toxicity similar to existing nicotine replacements.
According to this report, the level of carcinogens in electronic cigarettes is up to 1,000 times lower than regular cigarettes, and early evidence shows that electronic cigarettes may help people to stop smoking by simulating a tobacco cigarette.
On 27 March 2009, Health Canada issued an advisory against electronic cigarettes. The advisory stated, "Although these electronic smoking products may be marketed as a safer alternative to conventional tobacco products and, in some cases, as an aid to quitting smoking, electronic smoking products may pose risks such as nicotine poisoning and addiction."Canadian Customs now confiscate any parcel containing e-cigarettes with nicotine and notify the receiving party via a mail letter. The parcel is returned to the sender only at the request of the receiving party or otherwise destroyed.
Health New Zealand
In 2008, Dr. Murray Laugesen of Health New Zealand Ltd. published a report on the safety of Ruyan electronic cigarette cartridges. His study was funded by e-cigarette manufacturer Ruyan, but Laugesen claims that his research is independent. The presence of trace amounts of TSNAs in the cartridge solution was documented in the analysis. The results also indicated that the level of nicotine in the electronic cigarette cartridges was not different from the concentration of nicotine found in nicotine patches.John Britton, a lung specialist at the University of Nottingham, UK and chair of the Royal College of Physicians Tobacco Advisory Group, commented, "If the levels are as low as in nicotine replacement therapy, I don’t think there will be much of a problem."The study's detailed quantitative analysis concluded that carcinogens and toxicants are present only below harmful levels. It concluded: "Based on the manufacturer’s information, the composition of the cartridge liquid is not hazardous to health, if used as intended."
Dr. Konstantinos Farsalinos of the Onassis Cardiac Surgery Center in Athens reported to the annual meeting of the European Society of Cardiology that a small short-term trial had shown significantly better cardiac performance of ecigarette smokers in comparison to tobacco smokers. Farsalinos warned that larger studies were required to measure the long-term health impact of ecigarettes, but expressed some optimism: "Considering the extreme hazards associated with cigarette smoking, currently available data suggest that electronic cigarettes are far less harmful and substituting tobacco with electronic cigarettes may be beneficial to health." Another small study, also in Greece, reported earlier in 2012 the devices had little short-term impact on lung function.
A report from a UK Government advisory unit favoured the adoption of "smokeless nicotine cigarettes" over the traditional "quit or die" approach, believing this would save more lives.
While electronic cigarettes may deliver nicotine to the user in a manner similar to that of a nicotine inhaler, no electronic cigarette has yet been approved as a medicinal nicotine replacement therapy (NRT) product or subjected to the necessary clinical testing for such approval. Doubts have even been raised as to whether electronic cigarettes actually deliver any substantial amount of nicotine.
Research carried out at the University of East London on the effects of using an electronic cigarette to reduce cravings in regular tobacco smokers showed that there was no significant reported difference between smokers who inhaled vapour containing nicotine and those who inhaled a placebo vapour containing no nicotine. The report concluded that although electronic cigarettes can be effective in reducing nicotine-related withdrawal symptoms, the nicotine content does not appear to be of central importance, and other smoking related cues (such as taste or vapour resembling smoke) may account for the reduction in discomfort associated with tobacco abstinence in the short term.
In an online survey from November 2009 among 303 smokers, it was found that e-cigarette substitution for tobacco cigarettes resulted in reduced perceived health problems when compared to smoking conventional cigarettes (less cough, improved ability to exercise, improved sense of taste and smell).
Trace amounts of 'volatile organic compounds', namely formaldehyde, as well as traces of ketones, mercury and tetramethylpyrazine, have been found in electronic cigarette vapour, but the quantities are significantly smaller than the quantities found in tobacco smoke and do not pose a significant health risk.