Society For Risk Analysis Annual Meeting 2017

Session Schedule & Abstracts

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Common abbreviations

Symposium: To Vape or Not To Vape: Risks of E-cigarette Use

Room: Salon 1   1:30 pm–3:00 pm

Chair(s): Sara Henry

Sponsored by Dose Response and Risk, Policy & Law Specialty Groups

Use of e-cigarettes or vaporized nicotine products (VPNs)among youth has grown astronomically, while smoking has fallen significantly. Public health questions arise about vaping, especially about youth usage and what has become a $3.5 billion industry. Some public health experts express concern about nicotine addiction; others say vaping may help adults quit cigarette smoking. Vaping parlors offer a dizzying array of flavors, such as cotton candy and gummy bear, most of which have not been tested for inhalation toxicity. VPNs are regulated in some 55 countries; in 2016 a proposed regulation by the U.S. Food and Drug Administration Center for Tobacco Products (FDA/CTP) included a ban on sales of VPNs to those younger than 18 and would have required manufacturers to disclose their ingredients and submit their products to FDA/CTP for approval. The current administration has withdrawn this rule. This symposium is the third in a series addressing new research on the health risks of vaping. In mice genes in developing brains in utero exposed to VPN vapors with and without nicotine at concentrations comparable to human exposure showed altered activity in these rodents later in life which could indicate effects on memory. Activity of immune cells from humans exposed to VPN flavor ingredients was suppressed. In mice exposed to VPN vapor, as well as cigarette smoke, increased plaque buildup resulted, indicating beginning atherosclerosis. The impact of use of VPNs on health, especially in youth, will be discussed, as well as the contribution of VPNs to nicotine addiction. The symposium will be followed by a panel discussion

W3-J.1  1:30 pm  Health Effects Associated with E-cigarettes in Vulnerable Populations . Zelikoff JT*, Lauterstein D, Gordon T; New York University School of Medicine

Abstract: There is a general perception among the public that electronic (e)-cigarettes are safer than conventional cigarettes, and a growing number of pregnant women share this belief. Approximately 10% of all pregnant women who smoke in the U.S. continue conventional cigarette use during pregnancy. Up to 40% of all women who quit smoking conventional cigarettes in preparation for and/or during pregnancy resume smoking after pregnancy. These “ex” smokers are particularly vulnerable to e-cigarette use, as they perceive that e-cigarettes are a “safer” way for pregnant women to maintain their ability to “smoke”. Propylene glycol and glycerol, two of the main ingredients in e-cigarette liquids, are generally regarded as safe when ingested, but information concerning effects of these agents via inhalation is severely lacking. While not currently validated or confirmed scientifically, nicotine-replacement therapy products (e.g., nicotine patches or gum) appear to be less harmful to the fetus than conventional cigarettes and based on this, e-cigarettes may eventually prove to also be a “safer” alternative. However, the safe use of these products during pregnancy remains uncertain as data are lacking regarding the safety of these constituents for pregnant women/developing fetus as well as potential for harm to children from exposure to secondhand e-cigarette aerosols. In addition, our recent data demonstrate that e-cigarette use during pregnancy poses a potential threat to the developing brain, as nicotine is a known neurotoxicant. The proposed studies will generate scientific knowledge that can be readily translated to policy and serve as a guide for regulatory decisions and actions.

W3-J.2  1:50 pm  Getting a “Flavor” for Cardiovascular Effects of New and Emerging Tobacco Products. Conklin DJ*; University of Louisville

Abstract: Emerging tobacco-derived products including electronic cigarettes, smokeless tobacco (e.g., snus) and hookah (water pipe) contain, deliver and/or generate a number of harmful or potentially harmful constituents (HPHCs). Moreover, these products often contain flavorants that are generally regarded as safe (GRAS) for ingestion, however, most GRAS flavors have never been tested for their toxicity when heated and inhaled, which leaves uncertainty regarding the health risks of these products. An enormous (>8,000) number of flavors in e-juices/e-liquids are on the market including fruity, spicy and buttery flavors that attract youth to try these products. Moreover, there is precedent for concern of inhaling flavorant compounds, e.g., inhalation exposure to diacetyl, a component of buttery flavoring, is associated with a serious, fatal lung disease known as bronchiolitis obliterans in workers at a microwave popcorn manufacturing plant. Similarly disconcerting is that flavorants when heated can decompose into HPHCs, e.g., aldehydes. The cardiovascular effects of these HPHCs are understudied. Thus, there is a need to assess cardiovascular toxicity of flavors in general, and thus, we developed a screen to identify flavors with high cardiovascular toxicity in vitro. We used cardiomyocytes, endothelial cells, and platelets in cardiovascular toxicity assay. A series of flavor compounds were used based on chemical class and prevalence/abundance in tobacco products, such as cinnamaldehyde and menthol. We also tested whether flavorant toxicity was altered by low (<200 ºC) and high >700 ºC) temperature heating, which simulated temperatures encountered in tobacco products. Flavorant toxicity profiles in cardiovascular targets in vitro provides a starting point for assessing flavor-induced cardiovascular toxicity in vivo, and these data may inform future human studies to better estimate cardiovascular disease risk.

W3-J.3  2:10 pm  Human studies to determine the effects of flavored E-cigarettes on Respiratory immune responses. Jaspers, I I*; University of North Carolina at Chapel Hill

Abstract: While cigarette smoking impairs innate host defense responses, how vaping e-cigs modifies respiratory immune responses is completely unknown. Using non-invasive sampling of the nasal mucosa, ex vivo analyses, human in vivo infection models, as well as in vitro experiments our studies are designed to determine how vaping e-cigs affects respiratory host defense responses. Analysis of the nasal mucosa from non-smokers, cigarette smokers, and e-cig users showed that suppression of immune genes was larger in magnitude and broader in number than those seen in cigarette smokers. Assessing nasal mucosal mediators in non-smokers, cigarette smokers, and e-cig users showed enhanced levels of inflammatory cytokines, while mediators associated with recruitment and activation of immune cells were decreased in e-cig users. In addition, we used infection with the live attenuated influenza virus (LAIV) vaccine in humans in vivo to determine how vaping e-cigarettes affect antiviral host defense responses. Our data indicate that antiviral responses are significantly modified in e-cig users with a suppression of interferon-dependent host defense responses. In separate in vitro experiments, we examined the effects of flavored e-cigs on respiratory mucosal immune responses, specifically focusing on flavored e-cigarettes containing the popular flavoring agents, such as cinnamaldehyde, menthol, and vanillin. Our data indicate that cinnamaldehyde-containing e-liquids significantly suppress innate immune cell function in a dose-dependent manner without causing overt cytotoxicity, resulting in inhibition of immune cell function (IC50) at levels well below those causing cytotoxicity (LC50). In summary, using translational human in vitro and in vivo approaches, our studies examined whether exposure to flavored e-cigs has an immune suppressive effect on the respiratory mucosa in humans in vivo and whether specific flavoring agents induce dose-dependent effects in mucosal immune cells.

W3-J.4  2:30 pm  Quantitative risk assessment of tobacco related toxicants: comparisons between combusted and heated tobacco products. Meredith C*, Fiebelkorn SA; British American Tobacco

Abstract: Over 6500 components have been identified in the smoke from combusted cigarettes, many of which have established toxicological properties and may be important drivers of tobacco-related disease. We have reported previously on the use of risk prioritization tools such as Margins of Exposure (MoE) and risk assessment tools such as Incremental Lifetime Cancer Risk (ILCR) to assess the contribution of individual smoke toxicants to tobacco-related disease. Next generation products such as those that heat tobacco (to a maximum of 240°C) show levels of key toxicants in their emissions that are substantially reduced relative to the emissions from combusted products. Applying similar principles of MOE/ILCR analysis to individual toxicants in the emissions from a heated tobacco product reveals that the margins of exposure are increased substantially relative to the emissions from a combusted 3R4F reference product. Similarly, the ILCR calculated for the levels of the tobacco-specific nitrosamine NNK in the emissions from a heated tobacco product decreases substantially when compared to the levels in the emissions from the combusted 3R4F reference product. For groups of toxicants with similar modes of action (MOA), cumulative risk assessments can be considered. Overall these quantitative risk assessments on key tobacco related toxicants add to increasing evidence of the efficacy of heated tobacco products as a potential reduced exposure product.

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