Smoking, vaping and using nicotine pouches may carry different levels of danger, but all nicotine-containing products can harm cardiovascular health, according to a major review published in Nature Reviews Cardiology.
Researchers found that nicotine itself can affect the heart and blood vessels, even when it is delivered without cigarette smoke or tobacco combustion.
The review does not suggest that every nicotine product carries the same level of risk. Conventional cigarettes and waterpipes remain the most harmful forms because burning tobacco produces a wide range of toxic substances.
However, the researchers said removing smoke does not eliminate cardiovascular risks linked to nicotine. They described a “cardiovascular continuum of harm”, with combustible tobacco at the highest end, followed by heated tobacco products, e-cigarettes and oral nicotine products such as chewing tobacco and nicotine pouches.
Thomas Münzel, lead author of the review and a professor at University Medical Centre Mainz in Germany, said products that avoid combustion reduce some harm but do not remove cardiovascular risks.
The researchers examined how nicotine affects the cardiovascular system, focusing on its effects on blood vessels and the biological processes that can contribute to atherosclerosis, high blood pressure, heart attacks and strokes.
They identified several mechanisms through which nicotine can impair blood vessel function. Nicotine affects the endothelium, the thin layer of cells lining blood vessels, by reducing prostacyclin, a substance that helps vessels relax, while increasing endothelin-1, which promotes blood vessel constriction.
Nicotine can also act directly on vascular smooth muscle cells that control the width of blood vessels. By affecting potassium channels and calcium regulation, nicotine can make vessels contract more readily.
The researchers also identified oxidative stress, arterial stiffness and inflammation as common effects associated with nicotine exposure.
Endothelial dysfunction was highlighted as an important early sign of cardiovascular damage. When blood vessels become less able to relax and more prone to constriction and inflammation, the risk of conditions affecting the cardiovascular system can increase.
Filippo Crea, another author of the review, said nicotine plays an active role in endothelial dysfunction, which can occur early in the development of cardiovascular disease.
The findings come as health authorities and governments examine how regulation should address the expanding range of nicotine products.
The European Union is preparing changes to its tobacco-control framework as cigarette smoking declines in some populations while use of e-cigarettes, heated tobacco products and nicotine pouches increases.
Münzel said the addictive nature of nicotine and its effects on the cardiovascular system supported a more consistent regulatory approach covering different nicotine products.
The researchers stressed that reducing exposure to tobacco smoke can lower cardiovascular harm, but they argued that avoiding nicotine altogether is the only way to remove risks directly associated with nicotine.
The review adds to ongoing debate over whether newer nicotine products should be treated primarily as alternatives to cigarettes or as products that carry their own health risks.
