Heated tobacco products cause immediate cardiovascular and genetic damage

Just one session of heated tobacco product use results in measurable damage to the blood vessels, according to a study published today (Tuesday) in the European Journal of Preventive Cardiology.

Researchers carried out detailed assessments of blood samples, blood pressure and how well blood vessels are functioning in healthy smokers before and after they used two tobacco sticks consumed back-to-back with a tobacco heating device. They say their results challenge claims that these products are substantially less harmful to the cardiovascular system compared with conventional cigarettes and highlight the need to consider all nicotine-containing products in public health policies.

The research was led by Dr Lea Strohm from the University Medical Center Mainz, Germany.

Heated tobacco products, such as IQOS, which heat tobacco rather than burn it, are often marketed as less harmful alternatives to conventional cigarettes. However, independent evidence on their immediate effects on cardiovascular health, and the body as a whole, remains limited."

Dr. Lea Strohm, University Medical Center Mainz, Germany

The research included a group of 30 adult smokers, with an average age of 34, who were otherwise healthy. Participants gave blood samples, had their blood pressure measured, and their blood vessels assessed with an ultrasound scan of the main artery in the right arm. Participants then used a heated tobacco product, and the same set of tests were repeated.

Comparing measurements taken before and after use, the researchers identified several changes. Firstly, systolic blood pressure increased by three millimetres of mercury. Secondly, blood vessel function decreased by 11%, as measured by flow-mediated dilation, which shows how much an artery widens in response to increased blood flow. Finally, there were also signs that oxygen delivery around the body was reduced. Venous O2 saturation, the percentage of oxygen bound to haemoglobin in blood returning to the heart, fell from around 71% to around 46%.

Researchers also found DNA damage to blood cells and an 'oxidative stress response', a sign that the cells are trying to defend themselves against damage.

Dr Strohm added: "Our findings demonstrate that these products are not biologically inert. Acute exposure was sufficient to induce vascular dysfunction, metabolic disturbances, and genetic damage in otherwise healthy smokers. These results challenge claims that heated tobacco products are substantially less harmful to the cardiovascular system compared with conventional cigarettes.

"This study provides a clear, controlled look at the immediate cardiovascular impact of heated tobacco use, but larger long-term studies are still needed to understand how long these effects last."

Co-author Professor Thomas Münzel, of the University Medical Center Mainz, Germany, said: "These findings are in line with the conclusions of our recent expert review in the European Heart Journal. No nicotine-containing product, whether smoked, heated, vaped or absorbed, can be considered safe for the heart and blood vessels.

Professor Münzel concluded, "Heated tobacco produces fewer combustion products, but it still delivers nicotine, which impairs the lining of the blood vessels, raises blood pressure, and promotes atherosclerosis. Policymakers must stop distinguishing between 'burned' and 'unburned' nicotine and regulate all nicotine products under one framework, with flavour restrictions, advertising bans and smoke-free laws that cover every product."