An electronic cigarette is a rechargeable device that produces an inhaled aerosol containing varying levels of nicotine, and inorganic and organic toxicants and carcinogenic compounds. The aerosol is generated by heating a solution of propylene glycol and glycerin with nicotine and flavoring ingredients at a high temperature. The e-cigarette was developed and marketed as a safer alternative to the regular cigarette which is known to be injurious to human health. However, published studies suggest that the aerosol of e-cigarette can also have adverse health effects. The main objective of this review is to briefly describe some consequences of e-cigarette smoking, and to present data showing that the resulting increased oxidative stress and inflammation are likely to be involved in effecting to lung damage. Other organs are also likely to be affected. The aerosol contains varying amounts of organic and inorganic toxicants as well as carcinogens, which might serve as the source of such deleterious events. In addition, the aerosol also contains nicotine, which is known to be addictive. E-cigarette smoking releases these toxicants into the air leading to inhalation by nonsmokers in residential or work place areas. Unlike regular tobacco smoke, the long-term consequences of direct and secondhand exposure to e-cigarette aerosol have not been extensively studied but based on available data, e-cigarette aerosol should be considered harmful to human health.
Keywords: Oxidative stress; carcinogens; e-cigarette aerosol; pro-inflammatory cytokines; ultrafine metal particles.