The points raised in this research letter are not new. This was originally published by the authors in a public comment to the IQOS Modified Risk Tobacco Product Application on Dec 4, 2017 (FDA-2017-D-3001-0118). A response was developed to address the issue and was incorporated into our Tobacco Products Scientific Advisory Committee material.
A detailed review and analysis of all study data can be found on here.
A public comment by Dr. Konstantinos Farsalinos, M.D., on November 24, 2017, can be found here.
The totality of evidence available to-date for THS clearly demonstrates that THS presents less risk of harm and can reduce the risk of smoking related diseases including cardiovascular diseases (CVD) compared to continued smoking. The study reported by the authors provides no reliable scientific information about the effects of THS on the risk of CVD. We agree that endothelial dysfunction is an important prognostic factor in the development of atherosclerosis, hypertension, and heart failure.
Furthermore, flow-mediated dilation (FMD) is an accepted non-invasive technique to assess endothelial function and is considered predictive of cardiovascular risk, but only when executed following a strictly standardized protocol (as published by the “International Brachial Artery Reactivity Task Force”) avoiding the ingestion of substances that affect FMD prior to measurement. In contrast, an acute change in FMD measured immediately after exposure to substances such as nicotine, as per experimental design of Nabavizadeh et al. are not predictive of cardiovascular risk. The effects observed in the study by Nabavizadeh et al. are actually expected, well-known short-term sympathomimetic effects of nicotine that are not predictive of the development of CVD in humans.