The cigarette market is changing fast. While sales of conventional cigarettes are falling, heated tobacco products and e-cigarettes are gaining ground. Tobacco companies are rushing to roll out new smoke-free products, intensifying competition.
But does switching from conventional cigarettes to e-cigarettes really help your health? It may be better than continuing to smoke conventional cigarettes. But the story changes when compared with quitting entirely.
In a large-scale study tracking about 5.15 million adult men in Korea, those who quit conventional cigarettes but continued to use e-cigarettes had a higher risk of cardiovascular disease than those who quit completely. Among those who had quit conventional cigarettes for a long time, the difference reached 70%.
A research team led by Professors Choi Seul-gi, Lee Ki-heon and Park Sang-min of Seoul National University College of Medicine analyzed changes in smoking habits among 5,159,538 adult men who underwent two health checkups in 2014–2015 and 2018, using data from the National Health Insurance Service. The results were published in 2021 in the American Heart Association journal Circulation.
The researchers divided participants into groups of those who continued to smoke conventional cigarettes, those who used both conventional cigarettes and e-cigarettes, those who quit conventional cigarettes and used only e-cigarettes, and those who quit conventional cigarettes and did not use e-cigarettes, and compared the risk of cardiovascular disease. Here, e-cigarettes include both liquid e-cigarettes and heated tobacco products.
The average age of those who used both conventional cigarettes and e-cigarettes was 41, lower than those who continued to smoke only conventional cigarettes (48). Among those who had quit conventional cigarettes, e-cigarette users were also younger.
To reduce such differences, the researchers adjusted for key factors including age, income, employment status, region of residence, alcohol use, exercise, past smoking amount, body mass index, blood pressure, blood glucose, and comorbidities.
As a result, the risk of cardiovascular disease among those who used both conventional cigarettes and e-cigarettes was 17% lower than among those who continued to smoke conventional cigarettes. Those who quit conventional cigarettes and used only e-cigarettes showed a 19% lower risk.
So if you cannot quit conventional cigarettes, is it better to switch to e-cigarettes?
This study alone cannot answer that. People who used e-cigarettes may have been more health-conscious to begin with, or may have had other lifestyle habits such as smoking fewer conventional cigarettes and exercising more.
In fact, those who used both conventional cigarettes and e-cigarettes tended to smoke fewer conventional cigarettes per day and exercise more often than those who continued to smoke only conventional cigarettes. The very reason for choosing e-cigarettes may be related to health. The researchers noted that it is difficult to measure and adjust for all such factors.
There are more limitations. The researchers assessed e-cigarette use with a survey asking whether participants had used them almost daily in the past month. It was therefore difficult to determine the exact duration or pattern of e-cigarette use. There were also limits to distinguishing those who used e-cigarettes temporarily during the quitting process from those who used them continuously.
The follow-up period was also short. Participants were followed from the second health checkup in 2018 through the end of 2019. At most, about two years. That is a short period for assessing the risk of diseases like cardiovascular disease that develop over a long time.
The researchers did not compare liquid e-cigarettes and heated tobacco products separately. Therefore, it is not possible to determine which product is more dangerous. The subjects were also limited to adult men, so the results cannot be directly applied to women.
What is clearer in this study is the comparison among those who quit conventional cigarettes.
Among those who quit conventional cigarettes within the past five years, e-cigarette users had a 31% higher risk of cardiovascular disease than nonusers. Even among those who had quit conventional cigarettes for more than five years, the risk among e-cigarette users was 70% higher. Of course, because this is an observational study, it cannot be concluded that e-cigarette use increased the risk of cardiovascular disease.
The researchers also concluded that while switching to e-cigarettes rather than continuing to smoke conventional cigarettes may reduce cardiovascular risk, after quitting conventional cigarettes, complete abstinence is associated with a lower risk of cardiovascular disease.
References
Circulation (2021), DOI: https://doi.org/10.1161/CIRCULATIONAHA.121.054967