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OCR for page 447
Glossary
Acceptable daily intake (ADI): The daily dosage of a drug or a chemical
residue that appears to present no appreciable risk to health during
the entire lifetime of a human being.
Age-adjusted cancer incidence or mortality: The incidence or mortality
rate for cancer, adjusted for differences in the age distribution of
the populations being compared, i.e., the study population and a
standard reference population.
Anticarcinogen: A substance that inhibits or eliminates the activity
of a carcinogen.
Antimutagen: A substance that inhibits or eliminates the activity of a
mutagen.
Antioxidant: A substance that retards oxidation. Examples include
vitamin C, vitamin E, and butylated hydroxyanisole (BHA).
Benign tumor: A tumor that is confined to the territory in which it
arises, i.e., it does not invade surrounding tissue or metastasize
to distant organs. These tumors can usually be excised by local
surgery.
Bioassay: A test in which living organisms are used.
Cancer: Any of the various types of malignant neoplasms. See malignant
tumor, neoplasm.
Carcinogen: A chemical, physical, or biological agent that increases the
incidence of cancer.
Carcinoma: Cancer in an epithelial tissue, including external epithelia
(mainly skin and linings of the gastrointestinal tract, lungs, and
cervix) and internal epithelia (which line glands such as the breast,
pancreas, and thyroid).
Cocarcinogenesis: A general term that refers to augmentation of tumor
induction.
Cohort: 1. A group of people with a defined history of exposure who
are studied for a specific length of time to determine cancer in-
cidence or mortality. 2. A group of individuals born within the
same time period (usually within 5 or sometimes 10 years of each
447
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44X Glossary
other). Such groups are called "birth cohorts." The diseases
among individuals in one birth cohort followed throughout their
lifetimes may be different from those in another, implying
differences in exposures to factors causing disease.
Complete carcinogen: An agent that can act as both initiator and
promoter.
Comutagen: A nonmutagenic substance that enhances the activity of
a mutagen or imparts mutagenic activity to another nonmutagenic
substance.
Contaminant: A substance that is present in foods or feed but is
not intentionally added.
Delaney Clause: Legislation passed by the U.S. Congress in 1958 that
forbids the addition to food any additives shown to be carcinogenic
in any species of animal or in humans.
Diet: The total composition of ingested food, including nutrients,
naturally occurring contaminants, and additives.
Dietary factors: Substances that are present in or characteristics
that are associated with the diet; for example, the amount of total
fat, dietary fiber, the ratio of saturated versus unsaturated fat,
and the method of cooking.
Environment: Anything external to humans, i.e., lifestyle factors and
anything to which humans are exposed, including all forms of radia-
tion and substances eaten, drunk, and inhaled. See lifestyle factors.
Epidemiology: The study of the distribution of diseases and their
determinants in human populations.
Epigenetic: As used in reference to cancer, an effect that does not
directly involve a change in the sequence of bases in DNA.
Dietary fiber: Generic name for plant materials that are resistant
to the action of normal digestive enzymes.
Food additive: Any substance that is added to food, either directly
or indirectly.
Food disappearance data or per capita intake. Crude estimates of food or
nutrients available for consumption by a specified population; based
on food production, imports, exports, etc. They do not reflect the
amount consumed since approximately 20% of the food is probably dis-
carded, wasted, or spoiled. In the absence of data on actual food
consumption, however, it may be the closest approximation of the per
capita dietary intake of that population.
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OCR for page 449
Glossary 449
Genotoxicity: The quality of being damaging to genetic material.
Hyperplasia: An increase in the number of cells in a tissue or organ.
Incidence: The number of new cases of a disease expressed as a rate,
i.e., the number of new cases of a disease occurring in a given
population during a specific period, divided by the total number of
persons at risk of developing the disease during that same period.
Initiator: An external stimulus or agent that produces a cell that
can become malignant under certain conditions. Initiation events may
be mutational changes in a cell's genetic material, where the change
is initially unexpressed and causes no detectable alteration in the
cell's growth pattern. The change is considered to be irreversible.
Latency or latent period: The interval between the first exposure
to a carcinogenic stimulus and the appearance of a clinically
diagnosable tumor. For a disease like cancer, which usually
involves a sequence of steps over a long period, the term
latent period may be ambiguous.
Leukemia: Cancers of the blood-forming organs, characterized by
abnormal proliferation and development of leukocytes (white-
blood cells) and their precursors in the blood, lymph, bone
marrow, and lymph glands.
Lifestyle factors: Identifiable and quantifiable parameters of living
(e.g., diet, smoking, drinking, hobbies) that are useful in
distinguishing population groups for epidemiological studies.
Lymphoma: A cancer of cells of the immune system (e.g., lymphocytes),
where the tumor is confined to lymph glands and related tissues,
such as the spleen.
Malignant tumor: A tumor with the potential for invading neighboring
tissue and/or metastasizing to distant body sites, or one that has
already done so.
Melanoma: Malignant melanoma is a cancer of the cells that produce the
pigment melanin.
Menarche: The age at which menstruation begins.
Metaplasia: The abnormal transformation of an adult (mature), fully
differentiated tissue of one kind into differentiated tissue of
another kind.
Metastasis: The spread of a malignancy to distant body sites by cancer
cells transported in blood or lymph circulation.
OCR for page 450
450 Glossary
Modifier: A substance that can alter the course of carcinogenesis.
Morbidity: The condition of being diseased, or the incidence or
prevalence of some particular disease. The morbidity rate is
equivalent to the incidence rate.
Mortality: The number of overall deaths, or deaths from a specific
disease, usually expressed as a rate, i.e., the number of deaths
from a disease in a given population during a specified period,
divided by the average number of people exposed to the disease and
at risk of dying from the disease during that time.
Mutagen: A chemical or physical agent that interacts with DNA to cause
a permanent, transmissible change in the genetic material of a cell.
Multiple myeloma: A malignant neoplasm of plasma cells usually arising
in the bone marrow. Also called myelomatosis.
Neoplasm: A new growth of tissue with the potential for uncontrolled
and progressive growth. A neoplasm may be benign or malignant.
Nutrient: A component of food (e.g., protein, fat, carbohydrates,
vitamins, minerals) that provides nourishment for growth and
maintenance of the organism.
Nutrition: The sum of the processes by which an organism utilizes the
chemical components of food (which may or may not be synthesized in
vivo) through metabolism to maintain the structural and biochemical
integrity of its cells, thereby ensuring its viability and repro-
ductive potential.
Papilloma: A benign epithelial neoplasm.
Per capita intake: See food disappearance data.
Permissible residue: The quantity of a residue (e.g., a pesticide
residue in or on a food crop) permitted when the product is
first made available for consumption. The value may be calculated
from the ADI (See acceptable daily intake).
Precancerous lesion: A lesion or visible abnormality that has a
significant probability of later developing into cancer.
Prevalence (point prevalence): The number of existing cases of a dis-
ease, usually expressed as a proportion, i.e., number of cases of
a disease in a given population at a specified time, divided by the
estimated number of eligible persons in the population at that same
time.
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Glossary 451
Promoter: An agent that causes an initiated cell to produce a tumor
after prolonged exposure. Promotion events or, more generally, late
events can occur only in "initiated" cells and are somewhat reversi-
ble. Discontinuation of exposure to a promoter before tumor develop-
ment may prevent the appearance of a tumor.
Pyrolysis: The decomposition of a substance by heat.
Recommended Dietary Allowance (RDA): The level of intake of essential
nutrients that is adequate to meet the nutritional needs of
practically all healthy persons, as judged by the Committee on
Dietary Allowances of the Food and Nutrition Board, National
Research Council.
Risk: As used in epidemiological sections of this report, risk refers to
the probability of occurrence of a disease (cancer) in a given
population.
Relative risk: An estimate obtained by dividing the incidence of cancer
in the exposed group by the incidence in the corresponding unexposed
or control group.
Sarcoma: Cancers of various supporting tissues of the body (e.g., bone
cells, blood vessels, fibrous tissue cells, muscle).
Synergism: When two or more substances enhance each other's effects,
achieving more than the sum of their individual effects.
Threshold dose: A non-zero dose below which exposure is safe and not
associated with risk.
Tolerance level: The maximum level or concentration of a drug or
chemical that is permitted in or on food at a specified time
during slaughter (or harvesting), processing, storage, and
marketing up to the time of consumption by an animal or human
being.
Transformed cell: A cell that has undergone both initiation and
promotion and has the potential for leading to the develoment of
a neoplasm.
Tumor: An uncontrolled and progressive growth of tissue. A neoplasm.
It encompasses both benign and malignant neoplasms, but occasionally
may refer merely to a swelling of tissue.
Unintentional residue or contaminant: The residue of a compound in
feed or food resulting from circumstances not intended to protect
the feed or food against attack by infectious or parasitic diseases.
The residue may be acquired during any phase in the growth, produc-
tion, processing, or storage of feed or food.
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Representative terms from entire chapter:
acceptable daily
