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Suggested Citation:"Glossary." Institute of Medicine. 1994. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington, DC: The National Academies Press. doi: 10.17226/2141.
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Glossary


Abnormal sperm parameters.

Refers to any deviation from the normal shape or form of sperm, sperm volume, or sperm motility.

Agent Blue.

Herbicide formulation consisting of cacodylic acid used during the Vietnam conflict as a contact herbicide for rapid defoliation.

Agent Green.

Herbicide formulation consisting of the n-butyl ester of 2,4,5-T used during the Vietnam conflict for crop destruction.

Agent Orange.

Herbicide formulation consisting of a 1:1 mixture of 2,4-D and 2,4,5-T used during the Vietnam conflict for general defoliation.

Agent Pink.

Herbicide formulation consisting of a 60:40 mixture of the n-butyl ester and the isobutyl ester of 2,4,5-T used during the Vietnam conflict for defoliation.

Agent Purple.

Herbicide formulation consisting of a 50:30:20 mixture of the n-butyl ester of 2,4-D, and the n-butyl and isobutyl esters of 2,4,5-T used during the Vietnam conflict for general defoliation.

Agent White.

Herbicide formulation consisting of a mixture of 2,4-D and picloram used during the Vietnam conflict for forest defoliation and long-term defoliation control.

Suggested Citation:"Glossary." Institute of Medicine. 1994. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington, DC: The National Academies Press. doi: 10.17226/2141.
×

Ah receptor.

Protein located within liver cells (and possibly other cells) that interacts with TCDD and other molecules and with specific sites on DNA to regulate DNA.

Altered lipid metabolism.

An interference in the body's normal processes in breaking down or building up the molecules that are fat-soluble, including fatty acids, glycerides, waxes, steroids, and certain vitamins.

Anencephaly.

Absence of the cranial vault, with cerebral hemispheres completely missing or reduced to small masses attached to the base of the skull.

Anergy.

Absence of an immune reaction to a specific antigen.

Aphasia.

Loss or impairment of the ability to use or comprehend words usually resulting from a brain lesion.

Apraxia.

Loss or impairment of the ability to execute complex coordinated movements, without impairment of the muscles or senses.

Autoimmune disease.

A disease involving a humoral or cell-mediated immunity to the tissues of one's own body. A failure of the immune system to discriminate between self and respondent.


Bioassay.

A procedure for estimating the nature, constitution, or potency of a material by statistically analyzing the reaction that follows its application to living matter.


C-123.

Fixed-wing aircraft used in Operation Ranch Hand during the Vietnam conflict to spray herbicides.

Cacodylic Acid.

Dimethylarsinic acid, a contact herbicide used during the Vietnam conflict in Agent Blue.

Cancer.

A general term used to indicate a malignant tumor that expands locally by invasion or systemically by metastasis.

Cardiovascular disorders.

Disorders of the heart and blood vessels or the circulation of blood through the body.

Case-control study.

An epidemiologic study in which persons are selected because they have a specific disease or other outcome (cases) and are compared to a control (referent comparison) group to evaluate whether there is a difference in their reported frequency of exposure to possible disease risk factors. Also termed a retrospective study or case-referent study.

Suggested Citation:"Glossary." Institute of Medicine. 1994. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington, DC: The National Academies Press. doi: 10.17226/2141.
×

Cell-mediated immunity.

Immune reaction mediated by T cells; in contrast to humoral immunity, which is antibody mediated.

Chloracne.

An acne-like eruption due to prolonged contact with certain chlorinated compounds.

Cleft palate.

A fissure in the midline of the palate due to failure of the two sides to fuse in embryonic development.

Cognitive disorders.

Disorders of the central nervous system involving cognitive decline, including memory problems and dementia.

Cohort study.

An epidemiologic study in which a defined group of persons known to be exposed to a potential disease risk factor is followed over time and compared to a group of persons who were not known to be exposed to the potential risk factor to evaluate the differences in rates of the outcome. Also termed a prospective study, follow-up study, incidence study, retrospective cohort, or historical cohort study.

Confidence interval (95%).

A range of values for the effect estimate within which the true value is thought to lie with a 95% level of confidence.

Confounder (Confounding factor).

A factor that is associated with both the exposure and outcome of interest and can distort the apparent magnitude of the effect of the study factor.


Diabetes mellitus.

Disorder of carbohydrate metabolism characterized by inadequate utilization or secretion of insulin.

2,4-Dichlorophenoxyacetic acid (2,4-D).

A chlorophenoxy acid used as an herbicide in the Vietnam conflict in Agents Orange, White, and Purple.

Dioxins.

A subset of halogenated aromatic hydrocarbon compounds.

Dose-response effect.

The relationship between an exposure and specified outcome in which a change in amount, intensity, or duration of exposure is associated with a change (either increase or decrease) in outcome.


Healthy worker effect.

The observation that lower mortality rates are found in occupational cohorts than in the general population. This is attributed to the fact that severely ill persons are usually not in the workforce.

Hematopoietic.

Pertaining or relating to the formation of blood cells.

Suggested Citation:"Glossary." Institute of Medicine. 1994. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington, DC: The National Academies Press. doi: 10.17226/2141.
×

Hodgkin's disease.

Malignant lymphoma characterized by progressive enlargement of the lymph nodes, liver, and spleen, and by progressive anemia.

Humoral immunity.

An immune reaction that can be transferred with immune serum (as opposed to cell-mediated immunity). In general, refers to resistance that results from the presence of a specific antibody.

Hydatidiform mole.

A mass or tumor formed in the uterus resulting from the abnormal development of an ovum.

Hydrocephaly.

Dilation of the cerebral ventricles, most often occurring secondarily to obstruction of the cerebrospinal fluid pathways and accompanied by an accumulation of cerebrospinal fluid within the skull. It is typically characterized by enlargement of the head, prominence of the forehead, brain atrophy, mental deterioration, and convulsions.

Hypospadias.

Congenital abnormality in males in which the opening of the urethra is on the underside of the penis.


Immune modulation.

Fluctuation in the body's immune function, either increase or decrease.

Incidence.

The number of instances of illness during a given period of time in a specified population.

Infertility.

Incapability of producing offspring.


Latency.

The time interval between exposure and disease manifestation or recognition.

Leukemia.

Acute or chronic disease characterized by an abnormal increase in the number of leukocytes found in the tissues of the body with or without a corresponding increase in the circulating blood.

Lymphoma.

Malignant tumor of lymphoid tissue.


Matching.

The process of making the study population and the comparison group comparable with respect to one or more confounding factors.

Melanoma.

A malignant neoplasm, derived from cells that are capable of forming melanin in the skin.

Microcephaly.

Abnormally small head circumference in relation to the size of the rest of the body, usually associated with mental retardation.

Suggested Citation:"Glossary." Institute of Medicine. 1994. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington, DC: The National Academies Press. doi: 10.17226/2141.
×

Military Assistance Command, Vietnam (MACV).

The headquarters of the American military senior general staff during the Vietnam conflict.

Motor/coordination dysfunction.

Central nervous system disorders involving motor difficulties, characterized by problems such as weakness, tremors, involuntary movements, incoordination, and gait/walking abnormalities.

Multiple myeloma.

Cancer of specific bone marrow cells characterized by bone marrow tumors in various bones of the body.


Neuropsychiatric disorders.

Central nervous system disorders including neurasthenia (a collection of symptoms including difficulty concentrating, headache, insomnia, and fatigue), depression, posttraumatic stress disorder (PTSD), and suicide.

Non-Hodgkin's lymphoma.

A heterogeneous group of malignant lymphomas, with the only common factor being the absence of the giant Reed-Sternberg cells characteristic of Hodgkin's disease.

Null hypothesis.

The statement that the results observed in the study were no different from what might have occurred as a result of chance alone.


Odds ratio.

Measure of association in case-control studies which estimates the ratio of odds of exposure among cases compared to the odds of exposure among controls. The measure approximates the relative risk.


Peripheral nervous system disorders.

Dysfunctions involving either the somatic nerves or the autonomic system, known as neuropathies.

Picloram.

4-amino-3,5,6-trichloropicolinic acid, a systemic herbicide used during the Vietnam conflict in Agent White.

Porphyria cutanea tarda (PCT).

Characterized by liver dysfunction and photosensitive cutaneous lesions, with hyperpigmentation and scleroderma-like changes in the skin. It is the result of excess porphyrin being excreted in the urine due to a deficiency in uroporphyrinogen decarboxylase. The term ''porphyria" refers to disorders involving the biosynthesis of heme, the oxygen-carrying component in blood.

Proportionate mortality ratio (PMR).

The number of the observed deaths from a particular cause in the study population per 100 total deaths in the same period.

Suggested Citation:"Glossary." Institute of Medicine. 1994. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington, DC: The National Academies Press. doi: 10.17226/2141.
×

Ranch Hand.

The U.S. Air Force tactical military operation designated responsible for the aerial spraying of herbicides during the Vietnam conflict.

Relative risk.

Ratio of the risk of a disease or outcome in persons exposed to a particular risk factor to the risk in unexposed persons.

Risk.

Probability that an event will occur.


Sarcoma.

Malignant neoplasm arising in tissue of mesodermal origin (e.g., connective tissue, bone, cartilage, or striated muscle).

Silviculture.

Duties in the care and maintenance of forests including planting and thinning.

Soft tissue sarcomas.

Diverse group of sarcomas arising in the soft somatic tissues that occur within and between organs.

Spina bifida.

Defective closure of the body encasement of the spinal cord, through which the cord and meninges are exposed and may protrude.

Spontaneous abortion.

Naturally occurring loss of a nonviable fetus.

Standardized morbidity ratio (SMbR).

Ratio of the number of incident cases of a disease observed in a study population to the number of deaths expected if the study population had the same rates as the standard population.

Standardized mortality ratio (SMR).

Ratio of the number of deaths observed in a study population to the number of deaths expected if the study population had the same rates as the standard population.

Stillbirth.

Birth of a dead fetus.


2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD).

A halogenated aromatic hydrocarbon compound found as a contaminant in the herbicide 2,4,5-T.

2,4,5-Trichlorophenoxyacetic acid (2,4,5-T).

A chlorophenoxy acid developed during World War II as an herbicide and used in the Vietnam conflict in Agents Orange, Purple, Pink, and Green. The production process can result in TCDD contamination.


Ulcer.

A break in skin or mucous membrane with loss of surface tissue, disintegration and necrosis of epithelial tissue.

Suggested Citation:"Glossary." Institute of Medicine. 1994. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington, DC: The National Academies Press. doi: 10.17226/2141.
×

Vietnam era.

Designated by presidential proclamation (May 7, 1975) as the time period from August 1964 through May 7, 1975.

Vietnam era veteran.

Used throughout this report to designate veterans that served in other locations than Vietnam during the time span of the Vietnam conflict.

Vietnam theater.

The geographic area of the Vietnam conflict encompassing the land, air, and sea areas of Cambodia, Laos, North and South Vietnam.

Suggested Citation:"Glossary." Institute of Medicine. 1994. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington, DC: The National Academies Press. doi: 10.17226/2141.
×
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Suggested Citation:"Glossary." Institute of Medicine. 1994. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington, DC: The National Academies Press. doi: 10.17226/2141.
×
Page 778
Suggested Citation:"Glossary." Institute of Medicine. 1994. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington, DC: The National Academies Press. doi: 10.17226/2141.
×
Page 779
Suggested Citation:"Glossary." Institute of Medicine. 1994. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington, DC: The National Academies Press. doi: 10.17226/2141.
×
Page 780
Suggested Citation:"Glossary." Institute of Medicine. 1994. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington, DC: The National Academies Press. doi: 10.17226/2141.
×
Page 781
Suggested Citation:"Glossary." Institute of Medicine. 1994. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington, DC: The National Academies Press. doi: 10.17226/2141.
×
Page 782
Suggested Citation:"Glossary." Institute of Medicine. 1994. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. Washington, DC: The National Academies Press. doi: 10.17226/2141.
×
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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam Get This Book
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Have U.S. military personnel experienced health problems from being exposed to Agent Orange, its dioxin contaminants, and other herbicides used in Vietnam? This definitive volume summarizes the strength of the evidence associating exposure during Vietnam service with cancer and other health effects and presents conclusions from an expert panel.

Veterans and Agent Orange provides a historical review of the issue, examines studies of populations, in addition to Vietnam veterans, environmentally and occupationally exposed to herbicides and dioxin, and discusses problems in study methodology. The core of the book presents:

  • What is known about the toxicology of the herbicides used in greatest quantities in Vietnam.
  • What is known about assessing exposure to herbicides and dioxin.
  • What can be determined from the wide range of epidemiological studies conducted by different authorities.
  • What is known about the relationship between exposure to herbicides and dioxin, and cancer, reproductive effects, neurobehavioral disorders, and other health effects.

The book describes research areas of continuing concern and offers recommendations for further research on the health effects of Agent Orange exposure among Vietnam veterans.

This volume will be critically important to both policymakers and physicians in the federal government, Vietnam veterans and their families, veterans organizations, researchers, and health professionals.

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