First Comparison: Health Risks of Cigarettes, E-Cigarettes, and Hookah

Introduction: Smoking is a leading cause of non-communicable diseases globally and a major risk factor for cardiovascular diseases (CVD) and lung diseases. In recent years, e-cigarettes have gained popularity, especially among the younger generation. However, there is considerable debate regarding the health risks of e-cigarettes compared to traditional cigarettes. Recently, researchers in Germany conducted a study comparing the health impacts of cigarettes, e-cigarettes, and hookah on human health and cardiovascular risks.

Currently, six of the top eight causes of death worldwide are related to smoking. The prevalence of tobacco is one of the greatest threats to public health and a primary cause of morbidity and mortality from cardiovascular diseases. Recently, researchers in Germany conducted a study comparing the health impacts of cigarettes, e-cigarettes, and hookah, finding that all three can cause arterial stiffness, inflammation, and DNA damage, leading to various health issues.

This study, led by Professor Thomas Münzel from the Department of Cardiology at the Mainz University Medical Center in Germany, was published on June 25 in the European Heart Journal. The title is "Effects of tobacco cigarettes, e-cigarettes, and waterpipe smoking on endothelial function and clinical outcomes".



In this study, scientists explored the effects of cigarettes, e-cigarettes, and hookah on human health and endothelial cell function for the first time. They reviewed existing evidence on the harmful chemicals produced by smoking and the mechanisms by which smoking affects the body. The researchers also compared the impacts of the three types of smoking on diseases such as stroke, heart disease, and lung cancer.

Previous studies have shown that smoking leads to endothelial dysfunction and vascular damage. Long-term exposure to tobacco smoke impairs acetylcholine-dependent vasodilation and coronary blood flow, which is associated with elevated plasma cholesterol levels. The research team found that, overall, cigarettes are more harmful than e-cigarettes. However, there is insufficient data on the effects of hookah and e-cigarettes on endothelial dysfunction. The researchers stated that the long-term effects of hookah and e-cigarettes require further investigation. They also noted that "the harms of hookah are not less than those of cigarettes, so hookah should not be considered a healthy alternative".



The effects of the three types of smoking on human endothelial function and antioxidant interventions



The chronic and acute effects of the three types of smoking on animal endothelial function

The researchers reviewed a series of studies that provided evidence of the harmfulness of the three types of smoking. Compared to non-smokers, smoking increases the risk of chronic obstructive pulmonary disease (COPD) by 704% for cigarettes, 218% for hookah, and 194% for e-cigarettes; smoking and hookah increase the risk of lung cancer by 1210% and 122%, respectively, while data on e-cigarettes is insufficient to draw reliable conclusions.

They also studied the effects of the three types of smoking on atherosclerosis, which is an important prognostic indicator of the risk of heart disease and stroke. Compared to non-smokers, smoking increases the risk of atherosclerosis by 10%, hookah by 9%, and e-cigarettes by 7%.

The first author of this review, Professor Thomas Münzel from the Department of Cardiology at the Mainz University Medical Center, stated: "Our review primarily focuses on the adverse effects of these three types of smoking on endothelial dysfunction and their relationship with oxidative stress, which is associated with clinical diseases. All three types of smoking lead to an increase in reactive oxygen species (such as superoxide) in vascular tissues. This decomposes nitric oxide released by endothelial cells, which is crucial for helping blood vessels dilate, preventing inflammation and arterial blockage."



The mechanisms by which smoking affects endothelial function

The researchers noted that the main toxic chemicals in e-cigarette vapor include formaldehyde and acrolein, along with trace amounts of transition metals and volatile organic compounds (VOCs), all of which can damage cells. In contrast, cigarettes and hookah contain more complex harmful chemicals. Hookah smoke contains solid particulate matter, primarily from the charcoal used to burn tobacco; cigarette smoke also contains lower concentrations of solid particulate matter. All three types of smoking contain nicotine, which is addictive and has harmful biological effects.



Toxic compounds in the three types of smoking

Professor Münzel stated: "The overlap of these different toxic compounds may be key to understanding the harmful effects of smoking on health, which requires further research in the future."

The researchers also observed the impact of smoking on COVID-19 infections. In the article, they wrote: "As outlined by the World Health Organization, smoking and hookah may exacerbate COVID-19 symptoms, including more severe outcomes such as requiring intensive care and mechanical ventilation."

They concluded: "Undoubtedly, quitting smoking remains the most effective way to prevent cardiovascular and respiratory diseases caused by smoking. Given the COVID-19 pandemic, this is even more critical, as the use of tobacco products may increase the risk of COVID-19-related cardiovascular and other serious complications."

Professor Münzel stated: "The WHO warns that although e-cigarettes seem to be less harmful than cigarettes, there is increasing evidence that e-cigarettes may also have adverse effects on the lungs, heart, and blood vessels, and that using e-cigarettes may increase the risk of COVID-19 infection."