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APPENDIX: I GLOSSARY Acute: Having a short course; of short duration. Animal study: A controlled laboratory experiment in which animals are exposed to an agent and the biological effects of this exposure are assessed. The exposure may be via food or water (ingestion), by injection, by external application or by inhalation. Typical effects that might be measured are tumor incidence or tissue and organ changes. Bias: Regarding epidemiologic studies, the operation of factors in a study's design or execution that erroneously lead to the appearance of a stronger or weaker association between the agent in question and disease than in fact exists. Bioassay: The determination of the activity of a sample of an agent by noting its effect on a live animal or an isolated organ preparation. Carcinogen: A substance or agent designated as capable of producing or initiating cancer. Carcinogen classification system: A system for stratifying the weight of evidence for human carcinogenicity, for example, the system followed by the EPA. The EPA system consists of

the following levels:. Group A -- carcinogenic to humans; Group 8-- probably carcinogenic to humans; Group C -- possibly carcinogenic to humans; Group D -- not classifiable as to human carcinogenicity; and Group E -- evidence of non-carcinogenicity for humans.1 Case-control study: A type of epidemiologic study which compares diseased persons (cases) with nondiseased persons (controls) in association with a common exposure to an agent. Chronic: Persisting over a long period of time. Regarding animal studies, refers to administration of the test substance over a period of several weeks or months. Cohort study: An epidemiologic study which examines the development of a disease in a group (cohort) of persons who are currently free of the disease. May assess exposure either prospectively or retrospectively. Confounding: As applied to epidemiologic studies, the situation in which the relationship between an agent and a disease appears stronger or weaker than it truly is due to the 1. The definitions for carcinogen classification system, dose- response assessment, exposure assessment, hazard identification, risk assessment, risk characterization and weight of evidence are taken from the EPA's 1986 "Guidelines for Carcinogen Risk Assessment," 51 Fed. Reg. 185, 33992-34003. - 2 -

influence of another. unknown or unrecognized factor. In confounding, the agent under consideration is associated with another agent (a confounding factor, or confounder) which is itself associated with either an increase or decrease in the incidence of the disease. Dose-response assessment: Part of a risk assessment. Defines the relationship between the dose of an agent and the probability of induction of a carcinogenic effect. Electromagnetic field (EMF) : Electromagnetic radiation which is created by moving electric charges. Electromagnetic radiation propagates outward from any object that carries an electrical current. Its electric component pushes or pulls charged particles, such as ions, in the direction of the field: the magnetic component acts on moving charged particles and pushes them perpendicular to their direction of motion. The electric field may be easily screened, but the magnetic field can travel through most matter without losing strength. Environmental tobacco smoke (ETS): Consists of smoke originating from the smoldering end of a tobacco product between puffs, e.g., sidestream smoke, and of smoke exhaled by the smoker. The components are released into the environment where they 3

are diluted by ambient air and undergo changes related to aging over time. Epidemiology: The branch of science concerned with the patterns of disease in human populations and the various factors that influence these patterns. Exposure assessment: Part of a risk assessment. Identifies populations exposed to the agent, describes their composition and size, and presents the types, magnitudes, frequencies and durations of exposure to the agent. Extremely low frequency (ELF) electric field: A field with a frequency range between three Hertz (Hz) to 300 Hz. An example of a prevalent man-made ELF field is that resulting from power lines. Hazard identification: Part of a risk assessment. A qualitative assessment of risk, dealing with the process of determining whether exposure to an agent has the potential to increase the incidence of cancer. It qualitatively answers the question of how likely an agent is to be a human carcinogen.

In vitro: Literally, within glass; used to refer to laboratory procedures conducted in a test tube or similar location, often involving preparations of cells or tissues. In vivo: Literally, within the living body; used to refer to laboratory procedures utilizing live animals. Mainstream smoke (MS): Tobacco smoke drawn through the butt end of a cigarette. Meta-analysis: A statistical technique for combining studies into a single analysis, designed to increase the ability to statistically detect an association if such an association is present. Mutagen: An agent that tends to increase the frequency or extent of mutation, i.e., physical or biochemical changes in the genetic material of an organism. Nonionizing radiation: Radiation which does not cause atoms or molecules to become positively or negatively charged (i.e., to become ions) when it impinges on matter. ~ O N W C!C ~ 0 4k - 5 -

Pharmacokinetics: The study of the action of chemical substances in the body over a period of time, including the processes of absorption, distribution, metabolism and excretion. Radio frequency (RF) field: A field with a frequency range of 10,000 Hz to 300 Gigahertz (GHz) (1 GHz - 1 billion Hz). Relative risk: The ratio of the incidence rate of a disease among individuals exposed to a particular risk factor to the incidence rate among unexposed individuals. Risk assessment: The determination of adverse health consequences from exposure to toxic agents. [Will be carried out independently from considerations of the consequences of regulatory action.) Includes one or more of the following components: hazard identification, dose-response assessment, exposure assessment and risk characterization. Risk characterization: Part of a risk assessment. Combines the results of exposure assessment and dose-response assessment to estimate a carcinogenic risk in quantitative terms. Risk management: A combination of risk assessment with the directives of regulatory legislation, together with socioeconomic, technical, political and other considerations, 6

to reach a decision as to whether or how much to control future exposure to suspected toxic agents. Short-term tests: In vitro (performed on cells or tissue cultures) tests for mutations, including tests for chromosome aberrations, DNA damage/repair and other transformations which provide supportive evidence of cellular changes and may give information on carcinogenic mechanisms. Sidestream smoke (SS): Smoke originating from the smoldering end of a tobacco product between puffs. Statistical significance: A procedure to quantify the probability that an observed outcome, e.g., an association between an exposure and a disease endpoint, arose from random variation alone. The scientific community often uses 5% as a standard level at which data are accepted as occurring other than by chance. This means that there is a 95% probability that the results are not attributable to chance. Toxicology: The scientific study of poisons, their actions, their detection and the treatment of the conditions produced by them. Weight of evidence: A framework utilized by the EPA for judging the likelihood that an agent is a human carcinogen. Three W - 7 -

major steps are involved: (1) characterization of evidence from human studies and from animal studies, individually; (2) combination of the characterizations of these two types of data into an indication of the overall weight of evidence; and (3) evaluation of all supporting information to determine if the overall weight of evidence should be modified. [See also definition for carcinogen classification system.) JFK/tks 10355443 - 8 -