J Physiol. 2020 Sep 25. doi: 10.1113/JP279754. Online ahead of print.
KEY POINTS: E-cigarettes are the newest nicotine delivery devices on the market, with a popular misconception of being safer than conventional tobacco, but the full cardiopulmonary consequences of e-cigarette use remain unknown. Inhalation of e-cigarette aerosols impacts pulmonary physiology, with short-term exposure leading to increased airway reactivity, while long-term exposure leads to increased airway resistance, airway obstruction and inflammation. Both short-term (weeks to months) and long-term (years to decades) inhalation of e-cigarette aerosols increase lung inflammation and airway reactivity, raising the concern that vapers will develop asthma, chronic obstructive lung disease (COPD) and chronic bronchitis. Almost nothing is known about the impact of chronic e-cigarette use on cardiovascular function in humans, but animal models have demonstrated that chronic e-cigarette exposure increases arterial stiffness, causes vascular dysfunction and directly impacts cardiac tissue structure and function, all of which predict that chronic inhalation of e-cigarette aerosols will lead to cardiovascular disease. In this era of rapidly increasing e-cigarette use, particularly in adolescents and young adults, more studies in both animal models and human subjects are desperately needed to define both the long- and short-term effects of e-cigarette use on human health.
ABSTRACT: E-cigarette aerosols are exceedingly different from conventional tobacco smoke, containing dozens of chemicals not found in cigarette smoke. It is highly likely that chronic use of e-cigarettes will induce pathologic changes in both the heart and lungs. Here we review human and animal studies published to date and summarize the cardiopulmonary physiologic changes caused by vaping. In terms of cardiac physiology, acute exposure to e-cigarette aerosols in human subjects led to increased blood pressure and heart rate, similar to traditional cigarettes. Chronic exposure to e-cigarette aerosols using animal models caused increased arterial stiffness, vascular endothelial changes, increased angiogenesis, cardiorenal fibrosis and increased atherosclerotic plaque formation. Pulmonary physiology is also affected by e-cigarette aerosol inhalation, with increased airway reactivity, airway obstruction, inflammation and emphysema. Research thus far demonstrates that the heart and lung undergo numerous changes in response to e-cigarette use, and disease development will depend on how those changes combine with both environmental and genetic factors. E-cigarettes have been advertised as a healthy alternative to cigarette smoking, and users are under the impression that vaping of e-cigarettes is harmless, but these claims that e-cigarettes are safer and healthier are not based on evidence. Data from both humans and animal models are consistent in demonstrating that vaping of e-cigarettes causes health effects both similar to and disparate from those of cigarette smoking. Further work is needed to define the long-term cardiopulmonary effects of e-cigarette use in humans. Abstract figure legend Data across both human and animal studies demonstrate that daily inhalation of e-cigarette or vaping device aerosols on a chronic basis will cause significant cardiopulmonary disease. The data is stronger for short-term (months to years) effects, with the majority coming from human studies of acute (minutes to hours) and sub-acute (weeks to months) e-cigarette use. There is no data on long-term (years to decades) health effects in human subjects, because these devices have only been regularly used for the last several years; however, the data in animal models consistently demonstrate adverse effects on both cardiac and pulmonary physiology with long term exposures. Because of the multitude of e-cigarette and vaping devices (cig-a-likes, vape pens, box Mods, pod devices, etc.) and the wide range of chemicals found within e-liquids, of which there are thousands on the market, data across studies is difficult to compare. Further detailed studies are needed to better define the long-term health effects of these popular devices, with an emphasis on defining the specific chemicals and devices associated with untoward physiologic effects. This article is protected by copyright. All rights reserved.