September 12, 2018

Stanton A. Glantz, PhD

More evidence that PMI IQOS is as bad as a cigarette: Vascular endothelial function is impaired by aerosol from a single IQOS HeatStick to the same extent as by cigarette smoke

Pooneh Nabavizadeh, Matt Springer and their colleagues at UCSF just pubished "Vascular endothelial function is impaired by aerosol from a single IQOS HeatStick to the same extent as by cigarette smoke" in Tobacco Control.

This paper is an experimental study using rats that found that exposure to IQOS aerosol was just as bad for disturbing normal functioning of arteries as conventional cigarette smoke, adding to all the other recent data showing that, while they are different from conventional cigarettes, they are just as bad in terms of biological effects.

Here is the abstract:

Background Heated tobacco products (also called ‘heat-not-burn’ products) heat tobacco at temperatures below that of combustion, causing nicotine and other compounds to aerosolise. One such product, IQOS from Philip Morris International, is being marketed internationally with claims of harm reduction. We sought to determine whether exposure to IQOS aerosol impairs arterial flow-mediated dilation (FMD), a measure of vascular endothelial function that is impaired by tobacco smoke.

Methods We exposed anaesthetised rats (n=8/group) via nose cone to IQOS aerosol from single HeatSticks, mainstream smoke from single Marlboro Red cigarettes or clean air for a series of consecutive 30 s cycles over 1.5–5 min. Each cycle consisted of 15 or 5 s of exposure followed by removal from the nose cone. We measured pre-exposure and postexposure FMD, and postexposure serum nicotine and cotinine.

Results FMD was impaired comparably by ten 15 s exposures and ten 5 s exposures to IQOS aerosol and to cigarette smoke, but not by clean air. Serum nicotine levels were similar to plasma levels after humans have smoked one cigarette, confirming that exposure conditions had real-world relevance. Postexposure nicotine levels were ~4.5-fold higher in rats exposed to IQOS than to cigarettes, despite nicotine being measured in the IQOS aerosol at ~63% the amount measured in smoke. When IQOS exposure was briefer, leading to comparable serum nicotine levels to the cigarette group, FMD was still comparably impaired.

Conclusions Acute exposures to IQOS aerosol impairs FMD in rats. IQOS use does not necessarily avoid the adverse cardiovascular effects of smoking cigarettes.

The full citation for the paper is Nabavizadeh P, Liu J, Havel CM, et al Vascular endothelial function is impaired by aerosol from a single IQOS HeatStick to the same extent as by cigarette smoke.  Tobacco Control Published Online First: 11 September 2018. doi: 10.1136/tobaccocontrol-2018-054325.  It is available for free here.

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