IQOS - a heat-not-burn (HnB) tobacco product - chemical composition and possible impact on oxidative stress and inflammatory response. A systematic review.

Objectives: This work attempts to summarize current knowledge about IQOS, the heat-not-burn tobacco products, their chemical composition and possible impact on oxidative stress and inflammatory response. Materials and Methods: The literature search was performed between January and April 2019 by a combination of terms: 'IQOS smoking', 'IQOS cigarette', 'I quit original smoking cigarette', 'heat-not-burn products', 'HnB tobacco products'. Results: The aim of IQOS system is to minimalize the exposure of its smokers to dangerous substances present in cigarette smoke and to lower the probability of development of tobacco-related diseases. As current studies suggest, this new heat-not-burn tobacco product emits significantly lower concentrations of tar, carbonyls, VOCs, CO, free radicals or nitrosamines when compared to conventional cigarette, and thus it may reduce health risk for smokers. However, it does not eliminate this risk of development of tobacco-related diseases. Discussion: For conventional tobacco smokers the IQOS products may be an alternative option, which helps to reduce exposure to hazardous and potentially hazardous constituents. However, for never-smokers using the IQOS cigarettes may develop an addiction or increase exposition to some substances, which may increase probability of tobacco-related diseases. Moreover, emission of unexpected substances depends on device cleaning strategy and puff regiments. Conclusions: There is only limited data about IQOS effect on smokers' health. The future investigation, especially comparison with healthy never-smokers or study of chronic exposure to IQOS, is needed.