G Scientific Committee on Emerging and Newly Identified Health Risks SCENIHR Addictiveness and Attractiveness of Tobacco Additives SCENIHR adopted this opinion by written procedure on 12 November 2010 Addictiveness and Attractiveness of Tobacco Additives About the Scientific Committees Three independent non-food Scientific Committees provide the Commission with the scientific advice it needs when preparing policy and proposals relating to consumer safety, public health and the environment. The Committees also draw the Commission's attention to the new or emerging problems which may pose an actual or potential threat. They are: the Scientific Committee on Consumer Safety (SCCS), the Scientific Committee on Health and Environmental Risks (SCHER) and the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR), and are made up of external experts. In addition, the Commission relies upon the work of the European Food Safety Authority (EFSA), the European Medicines Agency (EMA), the European Centre for Disease prevention and Control (ECDC) and the European Chemicals Agency (ECHA). SCENIHR This Committee deals with questions related to emerging or newly identified health and environmental risks and on broad, complex or multidisciplinary issues requiring a comprehensive assessment of risks to consumer safety or public health and related issues not covered by other Community risk assessment bodies. Examples of potential areas of activity include potential risks associated with interaction of risk factors, synergic effects, cumulative effects, antimicrobial resistance, new technologies such as nanotechnologies, medical devices including those incorporating substances of animal and/or human origin, tissue engineering, blood products, fertility reduction, cancer of endocrine organs, physical hazards such as noise and electromagnetic fields (from mobile phones, transmitters and electronically controlled home environments), and methodologies for assessing new risks. It may also be invited to address risks related to public health determinants and non-transmissible diseases. Scientific Committee members Anssi Auvinen, James Bridges, Kenneth Dawson, Wim De Jong, Philippe Hartemann, Peter Hoet, Thomas Jung, Mats-Olof Mattsson, Hannu Norppa, Jean-Marie Pagès, Ana Proykova, Eduardo Rodríguez-Farré, Klaus Schulze-Osthoff, Joachim Schüz, Mogens Thomsen, Theo Vermeire. Contact: European Commission DG Health & Consumers Directorate C: Public Health and Risk Assessment Unit C7 - Risk Assessment Office: B232 B-1049 Brussels [email protected] © European Union, 2010 ISSN 1831--4783 ISBN 978-92-79-12788-5 doi: 10.2772/39398 ND-AS-09-003-EN-N The opinions of the Scientific Committees present the views of the independent scientists who are members of the committees. They do not necessarily reflect the views of the European Commission. The opinions are published by the European Commission in their original language only. http://ec.europa.eu/health/scientific_committees/policy/index_en.htm 2 Addictiveness and Attractiveness of Tobacco Additives ACKNOWLEDGMENTS Members of the working group are acknowledged for their valuable contribution to this opinion. The members of the working group are: SCENIHR members: Dr. Mogens Thomsen (Chair and Rapporteur) Prof. Peter Hoet Prof. Mats-Olof Mattsson Prof. Eduardo Rodríguez-Farré External experts: Prof. Hans Gilljam, Karolinska Institute, Stockholm, Sweden Prof. Rafael Maldonado López, University Pompeu Fabra, Barcelona, Spain Prof. Ann McNeill, UK Centre for Tobacco Control Studies, Division of Epidemiology & Public Health, University of Nottingham, Nottingham, UK Dr. Marcus Munafò, University of Bristol, Bristol, UK Dr. Urmila Nair, German Cancer Research Center (DKFZ), Unit Cancer Prevention and WHO Collaborating Centre for Tobacco Control, Heidelberg, Germany Per Kim Nielsen, MSc, Danish Cancer Society, Copenhagen, Denmark PD Dr. Thomas Schulz, German Federal Institute for Risk Assessment (BfR), Berlin, Germany Dr. Jean-Pol Tassin, Inserm/CNRS/ University Paris VI, France Dr. Jan G.C. van Amsterdam, RIVM, Bilthoven, The Netherlands 3 Addictiveness and Attractiveness of Tobacco Additives ABSTRACT The Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) has been asked to evaluate the role of tobacco additives in the addictiveness and attractiveness of tobacco products. The criteria for dependence established in humans indicate that tobacco has a high addictive potential, but it remains difficult to assess the addictiveness of individual additives. In animal studies the addictive potency of the final tobacco product cannot be assessed. The reinforcing potency of drugs is measured after intravenous injections and suggests that the abuse liability of pure nicotine is weaker than the addictive potential of tobacco products in humans. The currently used methods to define addictiveness of nicotine and additives are thus not considered adequate. In humans, the positive correlation between tobacco consumption and dependence suggests that individuals with high nicotine levels in their blood are more dependent. In animal studies using self-administration, an inverted U-shaped dose-response curve has generally been revealed suggesting that the addictiveness of nicotine is not directly linear with the dose. There is however substantial variation in the response to nicotine in both animals and humans, and genetic factors probably play an important role. No tobacco additives which are addictive by themselves have so far been identified. However, sugars, polysaccharides and cellulose fibres which are naturally present in tobacco, or sugars added in high quantities to most tobacco products, give rise to numerous aldehydes, such as acetaldehyde, in tobacco smoke. Acetaldehyde given intravenously is self-administered and enhances the addictiveness of nicotine in experimental animals. Additives that facilitate deeper inhalation (e.g. menthol) or inhibit the metabolism of nicotine may enhance the addictiveness of nicotine indirectly. Substances such as ammonia that increase the pH of the tobacco and the smoke, result in higher amounts of uncharged nicotine. However, it is uncertain if more nicotine is absorbed with higher smoke pH. For smokeless tobacco it seems that an increased pH enhances nicotine absorption in the mouth. The methods used to quantify the addictive potency of additives have limitations because of technical challenges in experimentally manipulating the presence or absence of an additive in a tobacco product. Such experiments require large technical and financial resources. In addition, there are ethical issues if testing in humans is considered. Due to these limitations, the available methodologies are not considered adequate. A number of technical characteristics of cigarettes (paper, filter, packing, geometry) influence the content of different substances in the smoke and the size of smoke particles. Many smokers compensate for a lower dose of nicotine by increasing puff volume and frequency, and by deeper inhalation. The particle size of the smoke aerosol does not seem to substantially influence the exposure to nicotine. The technical characteristics of cigarettes may thus modulate smoking behaviour but it is uncertain if this leads to a higher risk of addiction. Attractiveness is defined as the stimulation to use a product. The attractiveness of tobacco products may be increased by a number of additives but is also influenced by external factors such as marketing, price etc. Animal models do not currently exist for the assessment of attractiveness. In humans, the attractiveness of individual tobacco products may be compared in panel studies, surveys, and by experimental measures. Another method is to experimentally adjust tobacco products to exclude or include individual additives and test responses to them. However, this type of research is difficult due to ethical considerations that will usually preclude human testing of tobacco products, particularly among non-users or children. The use of fruit and candy flavours seems to favour smoking initiation in young people. Menthol also attracts a number of smokers, in particular African Americans. Some additives decrease the harshness and increase the smoothness of the smoke. Certain 4 Addictiveness and Attractiveness of Tobacco Additives additives yield a full and white smoke and other additives reduce the lingering odour of the smoke in order to favour the acceptability of smoking to people around. Additives considered attractive may in principle lead to brand preference or a higher consumption of tobacco products. However, it remains difficult to distinguish the direct effects of these additives from indirect effects such as the marketing towards specific groups. Keywords: addictiveness, additives, attractiveness, cigarettes, cigars, nicotine, SCENIHR, smokeless tobacco, smoking, target groups, tobacco, waterpipe Opinion to be cited as: SCENIHR (Scientific Committee on Emerging and Newly Identified Health Risks), Addictiveness and Attractiveness of Tobacco Additives, 12 November 2010. 5 Addictiveness and Attractiveness of Tobacco Additives TABLE OF CONTENTS ACKNOWLEDGMENTS ........................................................................................... 3 ABSTRACT .......................................................................................................... 4 EXECUTIVE SUMMARY........................................................................................... 9 1. BACKGROUND