Blogs

In response to a membership-expressed desire to include more timely research at the Annual Meeting, the Scientific Program Committee (SPC) recently accepted two Hot Topic Sessions to the scientific program.

The Conundrum of the PFOA Human Half-Life: Findings from an International Collaboration

Tuesday, March 29, 3:00 PM–4:30 PM, San Diego Convention Center Room 7

The Steering Committee of the Alliance for Risk Assessment (ARA) opened a call for scientists interested in resolving what appeared to be a conundrum in the estimation of the half-life of perfluorooctanoate (PFOA) in humans. After this call, an Advisory Committee was formed from nominations received, and a subsequent invitation led to the development of three small independent working groups to review appropriate information and attempt a resolution. Initial findings were shared among these groups, and a consensus developed from the ensuing discussions. Many human observational studies have estimated the PFOA half-life. Nearly all the studies note the likely occurrence of unmonitored PFOA exposures, which would result in inflated values of the estimated PFOA half-life. Also, few of these studies estimated the half-life of PFOA isomers, the branched chains of which likely have shorter half-lives. This would result in deflated values of the estimated PFOA half-life. Fortunately, several studies appear to have mollified both of these potential problems, although these studies also include recognized difficulties. The developing consensus position from this international collaboration is that the likely PFOA half-life in humans lies in the general range of 0.5 to 1.5 years, based these latter studies.

GRAS Is Not Always Greener and Is Not Always Safer: The Cardiopulmonary Toxicity of Solvents and Flavorants of Electronic Nicotine Delivery Systems (ENDS)—What Is the US FDA Missing in 2021 Deeming Rules?

Wednesday, March 30, 1:45 PM–4:30 PM, San Diego Convention Center Ballroom 6A

Although the electronic nicotine delivery system (ENDS) industry claims that ENDS are “safer” than conventional cigarettes, stand-alone ENDS devices are not innocuous. ENDS aerosol is a complex mixture of particles plus gases, containing at least 30 different chemicals, including tobacco-specific nitrosamines, metals, volatile organic compounds, carcinogenic polycyclic aromatic hydrocarbons, and carbonyls. Thus, even though ENDS aerosol contains fewer chemicals than cigarette smoke, there is no consensus that there is a similar reduction in risk for cardiopulmonary diseases when comparing ENDS users to users of traditional combustible tobacco products. The compounds that contribute to cardiopulmonary injury and thus increase cardiopulmonary disease risk, including nicotine and numerous carbonyls (e.g., acrolein, acetaldehyde, and formaldehyde), are present in aerosols of ENDS. Moreover, ENDS have a dizzying array of flavorant mixtures, representing a complexity unprecedented in traditional tobacco products. As flavorants and solvents (propylene glycol:glycerin, PG:G) are Generally Regarded as Safe (GRAS) for ingestion, their potential to induce cardiopulmonary injury following heating and inhalation as in ENDS use has not been fully evaluated despite the ubiquitous presence of ENDS products in the marketplace for nearly a decade. Despite the recent US FDA 2021 deeming rule to ban major classes of sweet, candy, and fruity flavor profiles in ENDS to reduce risk of youth addiction, there remains characterizing flavors of tobacco and menthol/mint as well as PG:G solvents that still represent potentially high risk for cardiopulmonary injury and disease. This Hot Topic Session, with its experts in cardiopulmonary toxicity, was designed to focus on the unfinished work of understanding the risks for cardiopulmonary injury of ENDS use and to provide an up-to-date view of the gaps in knowledge required to be filled to best inform US FDA decision-making regarding ENDS to protect public health.

For complete session details, please visit the Online Planner or the SOT Event App.

The SPC is delighted to include these two Hot Topic Sessions in the 2022 scientific program, providing additional venues for the dissemination of new and exciting results.