AHA Scientific Statement Reviews the Cardiopulmonary Impact of E-Cigarettes

Jason J. Rose, MD

Credit: American Heart Association

A new scientific statement from the American Heart Association (AHA) summarizes the current literature on the impact of electronic nicotine delivery systems, or e-cigarettes, on cardiopulmonary health, and calls for increased research into the long-term health effects associated with their use.¹

The statement, “Cardiopulmonary Impact of Electronic Cigarettes and Vaping Products,” elaborated on the latest usage data, trends, and health impacts, existing basic and clinical scientific evidence surrounding e-cigarettes use, and recommendations on research priorities to clarify short- and long-term usage effects.

“E-cigarettes deliver numerous substances into the body that are potentially harmful, including chemicals and other compounds that are likely not known to or understood by the user,” Jason J. Rose, MD, the volunteer chair of the scientific statement writing community and associate dean of innovation and physician science development at the University of Maryland School of Medicine in Baltimore, said in a statement.² “There is research indicating that nicotine-containing e-cigarettes are associated with acute changes in several hemodynamic measures, including increases in blood pressure and heart rate. There has also been research indicating that even when nicotine is not present, ingredients in e-cigarettes, particularly flavoring agents, independently carry risks associated with heart and lung diseases in animals. Negative effects of e-cigarettes have been shown through in vitro studies and in studies of individuals exposed to chemicals in commercially available products.”

E-cigarettes are battery-operated systems that heat a liquid solution to create an aerosol then inhaled into the lungs. Most formulations deliver nicotine, an addictive property and one to known to cause negative health effects, but can also contain other substances, including tetrahydrocannabinol (THC), methamphetamine, methadone, or vitamins. These liquids can include humectants that create a water aerosol or vapor, flavoring agents, cooling agents, metals from the heating coil, and other chemicals.

First recognized by the Centers for Disease Control and Prevention (CDC) in 2019, the writing committee suggests the significance of the clinical diagnosis of E-cigarette, or Vaping, product use Associated Lung Injury (EVALI). Approximately 2,800 hospitalizations in 2019 occurred among e-cigarette users in less than a year, emphasizing the lack of knowledge surrounding the risk of e-cigarettes. In many of these hospitalizations, vitamin E acetate was found as the ingredient that likely caused the illness, a substance that is sometimes used as a thickening agent in e-cigarette liquids.

There are limited studies focusing specifically on the impact of e-cigarettes on heart attacks and strokes, as much of the research has been performed on those with a history of or current use of traditional cigarettes. Age is another factor, as large survey studies have often focused on younger adults with a lower occurrence of heart attacks and strokes. As a result, there is a significant need for longer-term studies of e-cigarette users, including among those who already have cardiovascular disease

In the statement, investigators cited a recent analysis of the adult Population Assessment of Tobacco and Health (PATH) study found a statistically significant association between former or current e-cigarette use and the development of incident respiratory disease within the next 2 days. Other studies suggested a rapid increase since 2010 in the number of people who have ever used e-cigarettes or were currently using the devices, most being current or former traditional cigarette smokers. By 2016, data from the Behavioral Risk Factor Surveillance system suggested that 1.2 million adults in the US who had never smoked combustible cigarettes before were currently using e-cigarettes.

Youth are particularly affected, as e-cigarettes are the most used tobacco product among youth, often in high school- and middle school-aged students. The statements suggest almost 3 out of 4 young people using e-cigarettes exclusively use flavored products. The writing committee suggested young people may become attracted to the flavors available in the products and can subsequently develop nicotine dependence.

“There is significant concern about young people assuming e-cigarettes are not harmful because they are widely available and marketed to an age group that includes many people who have never used any tobacco products,” Rose said.² “The long-term risks of using e-cigarettes are unknown, but if the risks of chronic use are like combustible cigarettes, or even if the risks are reduced but still present, we may not observe them for decades. What is equally concerning is that studies show that some youth who use e-cigarettes go on to use other tobacco products, and there is also a correlation between e-cigarette use and substance use disorders.”

Other issues arise from the use of e-cigarette products as smoking cessation tools. Limited research has suggested any benefit that e-cigarettes may offer to help an individual’s smoking cessation is needed to be clearly balanced along the known and unknown potential health risks of these products. In fact, the statement suggests e-cigarette companies have promoted their products to quit smoking traditional cigarettes, but there is no strong evidence to support the claim beyond short-term benefits.

E-cigarette products are not approved by the US Food and Drug Administration (FDA) for tobacco cessation. The AHA instead recommends a combination of multiple-episode cessation counseling accompanied by personalized nicotine replacement therapy with FDA-approved doses and formulations, as well as medications to control cravings and help people who smoke combustible cigarettes with cessation.

“And all of this needs to be undertaken with the understanding that quitting often takes many tries, and any failures should be seen as just episodes to learn from on the road to finally beating a powerful addiction for good,” Rose Marie Robertson, MD, deputy chief science and medical officer at AHA and co-director of the AHA Tobacco Center of Regulatory Science, said in a statement.²

As a result, the scientific statement writing committee emphasized a critical need for additional knowledge and research regarding e-cigarette use, including:

• Future research on gaining knowledge about the serious and long-term effects of e-cigarettes on the heart, blood vessels, and lungs.
• Studies that include those with pre-existing cardiopulmonary disease to evaluate and compare outcomes among e-cigarette users in comparison to traditional smokers, dual users, and nonsmokers.
• In-depth research into common chemical ingredients in e-cigarettes and the effects they independently pose to pulmonary and cardiac health
• Clinical studies to investigate the risks and potential benefits of e-cigarettes as alternatives to traditional combustible cigarettes

The writing committee group noted the relative newness of e-cigarettes and other vaping systems in the US, being available in the country for about 15 years. Physicians and scientists thus do not yet have information on the long-term health effects of e-cigarettes, relying instead on shorter-term studies, molecular experiments, and animal research to assess their risks.

“It is necessary for us to expand this type of research since the adoption of e-cigarettes has grown exponentially, especially in young people, many of whom may have never used combustible cigarettes,” Rose said.²

References

1. Rose JJ, Krishnan-Sarin S, Exil VJ, et al. Cardiopulmonary Impact of Electronic Cigarettes and Vaping Products: A Scientific Statement From the American Heart Association [published online ahead of print, 2023 Jul 17]. Circulation. 2023;10.1161/CIR.0000000000001160. doi:10.1161/CIR.0000000000001160
2. Current evidence identifies health risks of e-cigarette use; long-term research needed. American Heart Association. July 17, 2023. Accessed July 18, 2023. https://newsroom.heart.org/news/current-evidence-identifies-health-risks-of-e-cigarette-use-long-term-research-needed.