Internal and Emergency Medicine | 2021
Examining the evidence for the health impact of combustion-free products: progress and prospects for tobacco harm reversal and reduction
Abstract
Chronic inhalational exposure to the mixture of more than 8000 harmful and potentially harmful chemical constituents that transfer into cigarette smoke during tobacco combustion can cause progressive functional alterations and structural damage in the human body, which result in numerous medical conditions affecting primarily the respiratory and cardiovascular systems [1, 2]. The key to reducing the negative health effects of smoking is to avoid chronic exposure to chemicals released during the tobacco combustion of conventional cigarettes. This can be achieved either by smoking cessation programs, which include prescription medications (varenicline, bupropion, nicotine replacement therapy) and counselling [3] or by cigarette substitution with combustion-free products, which include e-cigarettes and heated tobacco products (HTPs) [4]. Almost certainly smoking cessation programs and switching trials with non-combustible sources of nicotine would produce significant health improvements, thus confirming what might reasonably be predicted from what is already common knowledge on chemical composition of combustible cigarettes smoke and pathogenesis of smoking-related diseases. Switching from cigarettes to combustion-free products has been shown to improve respiratory outcomes in patients with COPD [5, 6] and to lower blood pressure in patients with hypertension [7]. Although these preliminary studies led to the expected results (i.e. that switching has similar clinical and functional benefits as quitting), their study design, sample size and reporting methods were not ideal. To reassure health and regulatory authorities, larger prospective studies on the long-term health impact of combustion-free nicotine delivery products (C-F NDPs) are needed. It is essential to provide high quality clinical information on the harm reduction/reversal potential of CF-NDPs as a substitute for conventional cigarettes for long-term use; switching studies may form an integral part of regulatory submissions to the US Food and Drug Administration (FDA) when seeking authorization to market a novel product as a modified-risk tobacco product (MRTP) [8]. Gale et al. describe their approach to substantiating the potential for harm reduction/reversal of a newly marketed HTP in their carefully designed switching trial, published in Internal and Emergency Medicine [9]. The HTP device in their study (glo) electronically heats (instead of burning) small tobacco sticks at temperatures below 250 °C to generate nicotine-containing aerosols. Because these aerosols are produced at temperatures below combustion (which generally begins at temperature above 400 °C), they contain much less harmful and potentially harmful chemicals than tobacco smoke, and the overall level of chemical exposure in exclusive HTP users is considerably lower than in smokers [10]. Gale et al. executed the valuable scientific step of performing a reality check on the prediction that avoiding exposure to combustible cigarettes smoke by switching to much less harmful HTPs would almost certainly produce significant health improvements. * Riccardo Polosa [email protected]