The health effects of electronic cigarette use: An overview

E-cigarettes were first introduced as smoking cessation aids and then expanded among non-smokers. E-cigarettes are relatively new and their impact on health has not been sufficiently explored, particularly in the long-term. The aim of this study was to review the effect of e-cigarettes on general and oral health. E-cigarette use is considered significantly less harmful than smoking though it is not deprived of health risks, which might vary depending on e-liquid and e-vapor content, manufacturing and storage conditions and prolonged use. Flavorings, propylene glycol, glycerin, aldehydes, heavy metal traces and nicotine are some of their hazardous compounds. E-cigarettes affect several cellular activities, such as inflammatory and apoptotic response, cellular metabolism and proliferation, commensal microbe proliferation and virulence. They have cytotoxic, genotoxic, and carcinogenic properties. Chronic use affects mostly the respiratory and cardiovascular systems and possibly the central nervous system. They increase heart rate, blood pressure, arterial stiffness and risks of presenting heart diseases that pave the way for cardiac arrhythmias. Periodontal tissues presented less inflammation with e-cigarettes than smoking. Periimplant tissues presented higher proinflammatory cytokine levels with e-cigarettes than never-smoking. Oral mucosal lesions were in total similarly prevalent for e-cigarette users and former smokers, though nicotine stomatitis, hairy tongue and angular cheilitis were more frequent with e-cigarettes. C. albicans carriage was higher with e-cigarettes than never-smoking. Switching from smoking to e-cigarettes may reduce oral and throat symptomatology, though several oral health consequences might be associated with e-cigarettes. Evidence supports that chronic e-cigarette use may affect health negatively. Taking into consideration that e-cigarettes might help quit smoking, health professionals should inform patients that smokers selecting e-cigarettes as smoking cessation aid should soon discontinue them since prolonged use entails health risks. Moreover, health professionals