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E-cigarettes using nicotine cause blood clotting and impair small blood vessels

Using e-cigarettes containing nicotine causes an immediate increase in the formation of blood clots and a deterioration in the ability of small blood vessels to expand and dilate, as well as raised heart rate and blood pressure, according to research presented at the European Respiratory Society International Congress.

According to European Respiratory Society (ERS) material published on 6 September 2021, researchers say these effects are similar to those caused by smoking traditional cigarettes and with long-term use, they could result in heart attack or stroke.

The study was presented by Gustaf Lyytinen, a clinician at Helsingborg Hospital and researcher at the Karolinska Institute in Stockholm, Sweden. He and his colleagues carried out detailed experiments with a group of 22 women and men aged between 18 and 45 years who were occasional smokers but otherwise healthy.

Each volunteer was tested before and after taking 30 puffs from an e-cigarette containing nicotine, and before and after 30 puffs from an e-cigarette not containing nicotine. These two sets of tests were carried out on separate occasions, at least one week apart.

On each occasion, the researchers measured volunteers’ heart rate and blood pressure and collected a blood sample before they used the e-cigarettes, then 15 minutes after use and again 60 minutes after use.

Researchers also carried out tests to measure any impact on the circulation of blood through the body’s tiny blood vessels, before volunteers used e-cigarettes and 30 minutes afterwards. These tests use a laser to visualise how well blood vessels in the skin are able to dilate and therefore regulate the supply of blood around the body.

Comparing the results of the tests, researchers found that using e-cigarettes containing nicotine created a set of immediate short-term changes in the volunteers.

Lyytinen and his team discovered an average 23% increase in blood clots after 15 minutes that returned to normal levels after 60 minutes. There were also increases in volunteers’ heart rates (from an average of 66 beats per minute/bpm to an average of 73bpm) and blood pressure (from an average of 108 millimetres of mercury/mmHg to an average of 117mmHg).

Researchers found that the volunteers’ blood vessels became temporarily narrower after they used nicotine-containing e-cigarettes.

These effects were not seen after volunteers used e-cigarettes that did not contain nicotine. Nicotine is known to increase levels of hormones such as adrenaline in the body, which in turn can increase the formation of blood clots.

Lyytinen said: “Our results suggest that using e-cigarettes that contain nicotine have similar impacts on the body as smoking traditional cigarettes. This effect on blood clots is important because we know that in the long-term this can lead to clogged up and narrower blood vessels, and that of course puts people at risk of heart attacks and strokes.”

Jonathan Grigg, who was not involved in the research, is Chair of the European Respiratory Society Tobacco Control Committee and Professor of Paediatric Respiratory and Environmental Medicine at Queen Mary University of London.

He said: “The damage caused by smoking traditional cigarettes, including the effects of nicotine on the body, are well-known. E-cigarettes are relatively new, so we know much less about what they do to the body.

“This study suggests that e-cigarettes containing nicotine can make clots form in users’ blood and make their small blood vessels less adaptable. This is a small study, so we’d like to see more research looking at these effects.

“Some people may use e-cigarettes when attempting to quit smoking because they are marketed as being safe, but this study adds to the growing evidence on the harmful effects of e-cigarettes. Other aids to quitting smoking which are evidenced-based and recommended by ERS, such as patches or gum, do not result in the lungs being exposed to high concentrations of potentially toxic compounds.”


Presentation details

Electronic cigarettes containing nicotine increase thrombotic activity and impair microcirculation.

Gustaf Lyytinen, Amelie Bryndal, Erik Anesäter, Lukasz Antoniewicz, Anders Blomberg, Håkan Wallen, Jenny Bosson, Linnea Hedman, Fariborz Mobarrez, Sara Tehrani and Magnus Lundbäck

Abstract published at the ERC International Congress on 6 September 2021.



Background and aims

Electronic cigarette (EC) vaping is increasingly popular despite growing evidence of adverse health effects. To further evaluate the impact of EC use on vascular health we have investigated effects of acute EC inhalation on haemostasis and microcirculation in healthy volunteers.


The study was performed in a double-blinded randomised crossover fashion. Twenty-two healthy young occasional tobacco users inhaled 30 puffs of EC with or without nicotine with a wash-out period of one week. Blood samples were collected at baseline, 15 and 60 minutes following exposure and analysed with Total-Thrombus-formation analysis system.

Two different chips, simulating fibrin-rich thrombus formation and platelet thrombus formation, were used. Microcirculation was assessed at baseline and 30 minutes after exposure by laser speckle contrast imaging and iontophoresis of acetylcholine and sodium-nitroprusside (SNP) to evaluate the endothelium-dependent and -independent pathways.


EC exposure with nicotine had several impacts compared to non-nicotine EC: Platelet thrombus formation and fibrin-rich thrombus formation increased significantly after 15 minutes (p=0.011 and p=0.035 respectively) following exposure and normalized after 60 minutes. Moreover, peak SNP-mediated microvascular flux, i.e. endothelium-independent vasodilation, was reduced following EC vaping with nicotine (p=0.009).


Thirty puffs of EC vapour with nicotine have acute adverse effects on thrombotic activity and endothelial independent microcirculation in healthy volunteers. No compelling effects of EC vaping without nicotine was observed, indicating nicotine as the main culprit.


European Respiratory Society material – E-cigarettes containing nicotine cause blood clotting and make small blood vessels less adaptable (Open access)


ERS International Congress session – Tobacco and nicotine research during the pandemic (Open access)

European Respiratory Society International Congress


See also from the MedicalBrief archives


Flavour additives in e-cigarettes may impair blood vessel function


E-cigarettes: What we know and what we don’t – Cancer Research UK


The health pros and cons of e-cigarettes – Evidence ambivalence


Lung symptoms common among users of e-cigarettes and related products




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