Agent Orange

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Studies and Reports

  • Lawson C et al., Paternal occupational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin and birth outcomes of offspring: birth weight, preterm delivery, and birth defects, Environ Health Perspect. 2004 Oct;112(14):1403-8.
    • Abstract. "Agent Orange is a phenoxy herbicide that was contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). We studied pregnancy outcomes among wives of male chemical workers who were highly exposed to chemicals contaminated with TCDD and among wives of nonexposed neighborhood referents. For exposed pregnancies, we estimated serum TCDD concentration at the time of conception using a pharmacokinetic model. The mean TCDD concentration for workers' births was 254 pg/g lipid (range, 3-16,340 pg/g). The mean referent concentration of 6 pg/g was assigned to pregnancies fathered by workers before exposure. A total of 1,117 live singleton births of 217 referent wives and 176 worker wives were included. Only full-term births were included in the birth weight analysis (greater than or equal to 37 weeks of gestation). Mean birth weight among full-term babies was similar among referents' babies (n = 604), preexposure workers' babies (n = 221), and exposed workers' babies (n = 292) (3,420, 3,347, and 3,442 g, respectively). Neither continuous nor categorical TCDD concentration had an effect on birth weight for term infants after adjustment for infant sex, mother's education, parity, prenatal cigarette smoking, and gestation length. An analysis to estimate potential direct exposure of the wives during periods of workers' exposure yielded a nonstatistically significant increase in infant birth weight of 130 g in the highest exposure group (TCDD concentration > 254 pg/g) compared with referents (p = 0.09). Mothers' reports of preterm delivery showed a somewhat protective association with paternal TCDD (log) concentration (odds ratio = 0.8; 95% confidence interval, 0.6-1.1). We also include descriptive information on reported birth defects. Because the estimated TCDD concentrations in this population were much higher than in other studies, the results indicate that TCDD is unlikely to increase the risk of low birth weight or preterm delivery through a paternal mechanism. Key words: birth defects, birth weight, congenital anomalies, dioxin, occupation, paternal exposure, preterm birth, TCDD."
  • Young A et al., Assessing possible exposures of ground troops to Agent Orange during the Vietnam War: the use of contemporary military records, Environ Sci Pollut Res Int. 2004;11(6):349-58.
    • Conclusions. "Historical information demonstrates that herbicide spray missions were carefully planned and that spraying only occurred when friendly forces were not located in the target area. RANCH HAND spray missions were either not approved or cancelled if approved when there were friendly forces in the area designated for spraying. Stringent criteria had to be met before spray missions could be approved. The operational information shows that spray missions for both defoliation and crop destruction were conducted in an extremely hostile environment. Heavy 'fighter suppression' with antipersonnel ordnance was used to minimize the impact of hostile ground fire on RANCH HAND aircraft. Procedures were in place that prohibited movement of troops into sprayed areas immediately after a mission due to the possible presence of unexploded ordnance delivered by fighter aircraft supporting RANCH HAND missions. The optimal nature of the spray equipment and application procedures minimized the possibility of significant spray drift. Conclusions. Few friendly troops were sprayed by fixed wing aircraft during Operation RANCH HAND, which delivered 95% of all defoliants used in Vietnam. Similarly, few troops were sprayed during helicopter or surface-based spray operations, which constituted the remaining 5% of defoliants. Detailed policies and procedures for approval and execution of spray missions ensured that friendly forces were not located in the areas targeted for spraying. Fighter aircraft assigned to accompany each spray mission frequently suppressed much of the hostile fire with bombs and other ordnance. Confirmed clearance of the target area was necessary to avoid friendly casualties. Historical records establish that these policies and procedures were strictly followed. Exposure of troops whether from direct spraying or movement through areas recently sprayed was very unlikely. The wartime military records of troop positions and herbicide operations are valuable for some purposes, but have specific limitations in exposure reconstruction. The completeness and accuracy of the geographic data (maps used by RANCH HAND and military ground units) were dependent upon the inherent precision of the map, the accuracy with which it depicted surface features, and the completeness and accuracy of the information on which it is based. Navigation by the crew using visual orientation and reference to the map was the only means that aircrew on spray missions had for establishing their locations. A Forward Air Controller independent of Operation RANCH HAND was present at the location of each spray target immediately before and during spraying operations to verify the target location and ensure that friendly forces were clear of the target area. Anecdotal reports of direct spraying of troops in Vietnam likely reflect the RANCH HAND missions spraying insecticide for mosquito control at regular intervals from March 1967 through February 1972. Outlook. The distribution and levels of serum dioxin in RANCH HAND veterans and the US Army Chemical Corps Vietnam veterans (the unit responsible for helicopter and ground-based spray operations) are distinguishable from typical levels in the population decades after the Vietnam conflict. An exposure model similar to that proposed in the 2003 report of the Institute of Medicine's Committee on 'Characterizing Exposure of Veterans to Agent Orange and Other Herbicides Used in Vietnam' was tested in 1988 by the Centers for Disease Control and Prevention and found to be a poor predictor of absorbed dose of TCDD. Military records during the Vietnam War lack the precision to determine that troops were directly sprayed with herbicides during Operation RANCH HAND, especially given the procedures in place to ensure clearance of friendly forces from the target area and the lack of elevated serum levels of TCDD in ground troops judged to have operated in heavily sprayed areas."
  • Young A et al., Environmental fate and bioavailability of Agent Orange and its associated dioxin during the Vietnam War, Environ Sci Pollut Res Int. 2004;11(6):359-70.
    • Conclusions. "The prospect of exposure to TCDD from Agent Orange in ground troops in Vietnam seems unlikely in light of the environmental dissipation of TCDD, little bioavailability, and the properties of the herbicides and circumstances of application that occurred. Photochemical degradation of TCDD and limited bioavailability of any residual TCDD present in soil or on vegetation suggest that dioxin concentrations in ground troops who served in Vietnam would have been small and indistinguishable from background levels even if they had been in recently treated areas. Laboratory and field data reported in the literature provide compelling evidence on the fate and dislodgeability of herbicide and TCDD in the environment. This evidence of the environmental fate and poor bioavailability of TCDD from Agent Orange is consistent with the observation of little or no exposure in the veterans who served in Vietnam. Appreciable accumulation of TCDD in veterans would have required repeated long-term direct skin contact of the type experienced by United States (US) Air Force RANCH HAND and US Army Chemical Corps personnel who handled or otherwise had direct contact with liquid herbicide, not from incidental exposure under field conditions where Agent Orange had been sprayed."
  • Young A and Newton M, Long overlooked historical information on Agent Orange and TCDD following massive applications of 2,4,5-T-containing herbicides, Eglin Air Force Base, Florida, Environ Sci Pollut Res Int. 2004;11(4):209-21.
    • Conclusion. "Since Agent Orange with its associated TCDD contaminant was aerially disseminated on the test grids, Test Area C-52A provided a 'field laboratory' for what may have happened in Vietnam, had there been no intercepting forest cover. However, in Vietnam a 'typical' mission would have disseminated 14.8 kg of 2,4,5-T/ha, most of which was intercepted by the forest canopy, versus the 876 kg 2,4,5-T/ha on the test grid at Eglin. Moreover, each hectare on the Eglin test grid received at least 1,300 times more TCDD than a hectare sprayed with Agent Orange in Vietnam. The disappearance or persistence of TCDD is dependent upon how it enters the ecosystem. Spray equipment test and evaluations missions at Eglin were generally scheduled and conducted with environmental conditions that were optimal for spray operations. This suggests that conditions favorable for dissemination of herbicide were the same conditions favorable for photodegradation of TCDD. It was likely that 99 percent of the TCDD never persisted beyond the day of application. No long-term adverse ecological effects were documented in these studies despite the massive quantities of herbicides and TCDD that were applied to the site. Reviews by the US Environmental Protection Agency and the National Academy of Sciences' Institute of Medicine did not address the fate of Agent Orange and TCDD as described in these studies from Eglin AFB, Florida."
  • Schnorr T et al., Spontaneous abortion, sex ratio, and paternal occupational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin, Environ Health Perspect. 2001 Nov;109(11):1127-32.
    • Abstract. "There is conflicting research regarding an association between fetal death and paternal exposure to Agent Orange, a phenoxy herbicide widely used in Vietnam that was contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Men who worked in the U.S. factories that produced Agent Orange were exposed to TCDD at levels hundreds of times higher than TCDD levels in the general population. Wives of TCDD-exposed chemical workers and wives of nonexposed neighborhood referents were interviewed to determine reproductive history. Paternal serum TCDD level at time of conception was estimated for each pregnancy using serum samples taken in 1987. Estimated TCDD levels of workers during or after exposure were high (median, 254 ppt; range, 3-16,340 ppt) compared to referent levels (median, 6 ppt; range, 2-19 ppt). No association between paternal TCDD level at the time of conception and spontaneous abortion was observed among pregnancies fathered by workers with TCDD levels of < 20 ppt [odds ratio (OR) = 0.77; 95% confidence interval (CI), 0.48-1.22], 20 to < 255 ppt (OR = 0.81; 95% CI, 0.40-1.63), 255 to < 1,120, (OR = 0.69; 95% CI, 0.30-1.58), and >or= 1,120 ppt (OR = 0.95; 95% CI, 0.42-2.17) compared to pregnancies fathered by referents. The sex ratio [males/(males + females)] of offspring also did not differ by TCDD exposure (0.53 and 0.54 among workers and referents, respectively). We did not find an association between paternal serum TCDD level and spontaneous abortion or sex ratio of offspring in this population. The estimated TCDD levels in this exposed worker population were much higher than in other studies, providing additional evidence that paternal TCDD exposure does not increase the risk of spontaneous abortion at levels above those observed in the general population. The study could not evaluate the effect of father's childhood or prenatal TCDD exposure on subsequent sex ratio.
  • Mahan C et al., A case-control study of lung cancer among Vietnam veterans, J Occup Environ Med. 1997 Aug;39(8):740-7.
    • Abstract. "Because of concerns among veterans over Agent Orange exposure, the Department of Veterans Affairs (VA) has conducted a series of studies of specific cancers among Vietnam veterans. Lung cancer is the topic of investigation in this report. The VA's Patient Treatment File (PTF) was used to identify 329 Vietnam era veterans with a diagnosis of lung cancer made between 1983 and 1990. The PTF is a computerized hospitalized database of inpatient records, including patients' demographic data, and diagnoses. A record is created for each patient discharged from any one of the VA's Medical Centers. Variables abstracted from the military record include education, race, branch of service, Military Occupational Specialty Code, rank, and units served within Vietnam. Two hundred sixty-nine controls were randomly selected from the PTF file of men hospitalized for a reason other than cancer. A second control group numbering 111 patients with colon cancer was also selected from the PTF file. Data were also gathered on exposure to Agent Orange through the location of each individual ground troop veteran's unit in relation to an area sprayed and the time elapsed since that area was sprayed. The crude odds ratio between service in Vietnam and lung cancer was of borderline significance (odds ratio = 1.39 with 95% confidence interval = 1.01-1.92). The relationship disappeared when the confounder year of birth was considered. We conclude from these data that there is no evidence of increased risk in lung cancer associated with service in Vietnam at this time."
  • Bullman T et al., Risk of testicular cancer associated with surrogate measures of Agent Orange exposure among Vietnam veterans on the Agent Orange Registry, Ann Epidemiol. 1994 Jan;4(1):11-6.
    • Abstract. "A case-control analysis was undertaken to examine the association between various surrogate measures of Agent Orange exposure and testicular cancer among Vietnam veterans. Study subjects were selected from the Department of Veterans Affairs Agent Orange Registry. The case patients consisted of 97 veterans with a diagnosis of testicular cancer, and 311 veterans without any clinical diagnosis served as a comparison group. The surrogate measures were branch of service, type of duty, corps area, and location of the individual's unit in relation to recorded Agent Orange spray tracts. Only Navy veterans had a statistically significant increased risk of testicular cancer (odds ratio (OR) = 2.60; 95% confidence interval (CI), 1.08 to 6.24). Risk of testicular cancer was not significantly increased for ground troops (OR = 0.46; 95% CI, 0.25 to 0.86), for combat duty (OR = 0.91; 95% CI, 0.52 to 1.58), for service in the III Corps area (OR = 1.10; 95% CI, 0.66 to 1.84), and for being close to spray tracts within 90 days/8 km (OR = 0.99; 95% CI, 0.54 to 1.84) or 3 days/2 km (OR = 1.39; 95% CI, 0.50 to 3.80). The study results are not consistent with the hypothesis that Agent Orange may be a risk factor for testicular cancer among Vietnam veterans."
  • Tamburro C., Chronic liver injury in phenoxy herbicide-exposed Vietnam veterans, Environ Res. 1992 Oct;59(1):175-88.
    • Abstract. "Reports of hepatotoxic injury in Vietnam veterans exposed to phenoxy herbicides (mainly, 2,4-D and 2,4,5-T) initiated a retrospective cohort study of veterans self-reporting exposure to Agent Orange (AO) while serving in Vietnam from 1962 to 1971. Historical, medical, and laboratory information was obtained in a subcohort of 100 randomly selected veterans from a pool of 350 registrants. An occupational work exposure ranking system was designed to estimate individual exposure to phenoxy herbicide and its contaminant, dioxin (TCDD). Job classifications were determined by military job codes. Military application of the herbicides used in Vietnam were derived from the National Research Council Report based on the Herbs tapes. Health examination included tests of body systems affected by TCDD and similar agents, e.g., hemopoietic system, cholesterol/lipid metabolism, hepatic function, and skin lesions. Skin rash was utilized as a marker disease, since no case of true chloracne was found among the cohort. The cohort was divided into those with (R) and without (NR) a reported rash during or after the Vietnam tour. The R group had higher frequency (31%) of abnormal liver studies of all types than the NR group (18%). Of the 14 Vietnam veterans with persistent serum transaminase elevations, 86% reported a rash. Abnormal liver functions correlated with herbicide exposure index in both groups, but was more prominent in the R group. Study of the exposure index components showed that the liver abnormalities were related to the months of exposure and not to job classification or exposure rank. Viral hepatitis and alcoholism among both groups accounted for the association between liver abnormalities and cumulative exposure to AO. These data provide strong supportive evidence that chronic liver abnormalities among Vietnam veterans applying to the AO Registry are mainly due to viral or alcoholic causality and not to herbicides and their TCDD contaminant."
  • Dalager N et al., Non-Hodgkin's lymphoma among Vietnam veterans, J Occup Med. 1991 Jul;33(7):774-9.
    • Abstract. "In light of findings suggesting an increase in the risk for non-Hodgkin's lymphoma among men exposed to phenoxyherbicides and concerns among veterans over Agent Orange exposure, a hospital-based case-control study was undertaken to examine the association between military service in Vietnam and non-Hodgkin's lymphoma. The cases consisted of 201 Vietnam-era veteran patients who were treated in one of 172 Department of Veterans Affairs hospitals from 1969 through 1985 with a diagnosis of non-Hodgkin's lymphoma. 358 Vietnam-era veteran patients with a diagnosis other than malignant lymphoma served as a comparison group. Military service information was obtained from a review of the veteran's military personnel records. Service in Vietnam did not increase the risk of non-Hodgkin's lymphoma either in general (branch adjusted odds ratio = 1.03, 95% confidence interval = 0.70-1.50) or with increased latency period as defined as the duration in years from first service in Vietnam to hospital discharge. Surrogate measures of potential Agent Orange exposure such as service in a specific military branch, in a certain region within Vietnam, or in a combat role as determined by military occupational speciality were not associated with any increased risk of non-Hodgkin's lymphoma."
  • The association of selected cancers with service in the US military in Vietnam. III. Hodgkin's disease, nasal cancer, nasopharyngeal cancer, and primary liver cancer. The Selected Cancers Cooperative Study Group, Arch Intern Med. 1990 Dec;150(12):2495-505.
    • Abstract. "As part of a series of investigations into the health of Vietnam veterans, we conducted case-control studies involving 310 men with Hodgkin's disease, 48 with nasal carcinoma, 80 with nasopharyngeal carcinoma, 130 with primary liver cancer, and 1776 controls between 1984 and 1988. All men born between 1929 and 1953 and diagnosed in an area covered by eight cancer registries were considered eligible as cases; controls were recruited by random-digit dialing. Whereas the study had excellent power (96%) to detect a twofold increase in risk for Hodgkin's disease among Vietnam veterans, its ability to detect a similarly elevated risk in the other cancers was limited, ranging from 38% (nasal carcinoma) to 75% (primary liver cancer). Analyses showed that risks among Vietnam veterans relative to other men were 1.1 (Hodgkin's disease), 0.7 (nasal carcinoma), 0.5 (nasopharyngeal carcinoma), and 1.2 (primary liver cancer). None of these relative risks was significantly different from 1.0. Similar results were obtained if Vietnam veterans were compared with (1) other veterans or (2) men who never served in the military. An examination of several attributes of military service in Vietnam (eg, branch, duration of service, and other characteristics that may have been associated with the use of Agent Orange) failed to identify any groups of veterans who were at increased risk for Hodgkin's disease. Small numbers limited further analyses of nasal, nasopharyngeal, and liver cancer. These results provide no evidence that, 15 to 25 years following service in Vietnam, the risk of these malignant neoplasms is higher among veterans."
  • The association of selected cancers with service in the US military in Vietnam. II. Soft-tissue and other sarcomas. The Selected Cancers Cooperative Study Group, Arch Intern Med. 1990 Dec;150(12):2485-92.
    • Abstract. "As part of a series of investigations into the health of Vietnam veterans, we conducted a population-based, case-control study of soft-tissue and other sarcomas between 1984 and 1988. All men born between 1929 and 1953 and diagnosed in an area covered by eight cancer registries were considered eligible. Controls were selected by random-digit dialing. Analyses of 342 men with pathologically confirmed sarcoma and 1776 controls showed that Vietnam veterans had a relative risk of 1.0 for sarcoma in comparison with men who did not serve in Vietnam (95% confidence interval, 0.6 to 1.6). Restriction of the analysis to the 254 men with soft-tissue sarcoma yielded a relative risk of 0.9 (95% confidence interval, 0.5 to 1.6). Several attributes of military service in Vietnam (eg, branch, duration of service, military region, and other characteristics that may have been associated with the use of Agent Orange) were examined, and none was associated with an increased risk for the development of sarcoma. Furthermore, no morphologic type of sarcoma was overrepresented among Vietnam veterans. Results were unchanged if Vietnam veterans were compared with (1) other veterans or (2) men who never served in the military. This study, which had 97% power to detect a relative risk of 2.0 for all sarcomas, provides no evidence that the risk for the development of soft-tissue or other sarcomas is increased among veterans 15 to 25 years following service in Vietnam."
  • The association of selected cancers with service in the US military in Vietnam. I. Non-Hodgkin's lymphoma. The Selected Cancers Cooperative Study Group, Arch Intern Med. 1990 Dec;150(12):2473-83.
    • Abstract. "As part of a series of investigations into the health of Vietnam veterans, we conducted a population-based, case-control study of non-Hodgkin's lymphoma between 1984 and 1988. All men born between 1929 and 1953 and diagnosed as having non-Hodgkin's lymphoma in an area covered by eight cancer registries were considered eligible. Control subjects were identified by random-digit dialing from these same regions and were frequency-matched to men with lymphoma by age. Analyses of 1157 men with pathologically confirmed lymphomas and 1776 control subjects showed that the risk of non-Hodgkin's lymphoma was approximately 50% higher among Vietnam veterans (odds ratio, 1.47; 95% confidence interval, 1.1 to 2.0) compared with men who did not serve in Vietnam. Vietnam veterans were also at higher risk relative to (1) men who had not served in the military, (2) other veterans, and (3) other veterans who served between 1964 and 1972. An analysis of the military histories of the 232 Vietnam veterans suggested that the relative risk (1) increased with length of service in Vietnam (P = .10), and (2) was higher among men in the sea-based Navy than among other veterans (P = .11). Little difference in risk, however, was noted according to dates of service, type of unit, military region, or any other characteristics that may have been associated with the use of Agent Orange. Although the cause remains uncertain, results of this study indicate that the risk of non-Hodgkin's lymphoma is higher among Vietnam veterans than among other men."
  • Wolfe W et al., Health status of Air Force veterans occupationally exposed to herbicides in Vietnam. I. Physical health, JAMA. 1990 Oct 10;264(14):1824-31.
    • Abstract. "The Air Force Health Study is a 20-year comprehensive assessment of the health of Air Force veterans of Operation Ranch Hand, the unit responsible for aerial spraying of herbicides in Vietnam. The study compares the health and noncombat mortality of Ranch Hand veterans with a comparison group of Air Force veterans primarily involved with cargo missions in Southeast Asia but who were not exposed to herbicides. This report summarizes the health of these veterans as determined at the third in a series of physical examinations. Nine hundred ninety-five Ranch Hands and 1299 comparison subjects attended the second follow-up examination in 1987. The two groups were similar in reported health problems, diagnosed skin conditions, and hepatic, cardiovascular, and immune profiles. Ranch Hands have experienced significantly more basal cell carcinomas than comparison subjects. The two groups were not different with respect to melanoma and systemic cancer."
  • erum 2,3,7,8-tetrachlorodibenzo-p-dioxin levels in US Army Vietnam-era veterans. The Centers for Disease Control Veterans Health Studies, JAMA. 1988 Sep 2;260(9):1249-54.
    • Abstract. "This study investigates whether military records can be used to identify US Army Vietnam veterans who were likely to be exposed to the herbicide Agent Orange. Serum levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a toxic contaminant in Agent Orange, were obtained for 646 ground combat troops who served in heavily sprayed areas of Vietnam and for 97 veterans who did not serve in Vietnam. The distributions of current TCDD levels in Vietnam and non-Vietnam veterans were nearly identical (mean in each group, approximately equal to 4 parts per trillion [ppt]). Only two men (both Vietnam veterans) had clearly elevated levels (greater than 20 ppt). Levels of TCDD did not tend to increase with greater likelihood of exposure to Agent Orange, as estimated from either military records or self-reported exposure. This study is consistent with other studies and suggests that most US Army ground troops who served in Vietnam were not heavily exposed to TCDD, except perhaps men whose jobs involved handling herbicides."
  • Kang H et al., Soft tissue sarcoma and military service in Vietnam: a case-control study, J Natl Cancer Inst. 1987 Oct;79(4):693-9.
    • Abstract. "A case-control study was conducted in men who were of draftable age during the Vietnam conflict to examine the association of soft tissue sarcomas (STSs) with military service in Vietnam as well as other host and environmental risk factors. A total of 217 STS cases selected from the Armed Forces Institute of Pathology were compared to 599 controls for Vietnam service, occupational and nonoccupational exposure to various chemicals, occupational history, medical history, and life-style (smoking, alcohol, coffee, etc.). Military service information was verified by a review of the patient's military personnel records. Other information was ascertained from a telephone interview with either subjects or their next of kin. Cases and controls were stratified on the basis of the hospital type (civilian, Veterans Administration, and military); the Mantel-Haenszel estimate of the odds ratio (OR), adjusted for the effects of the stratification variable, was calculated. Vietnam veterans in general did not have an increased risk of STS when compared to those men who had never been in Vietnam (OR, 0.85; 95% confidence interval, 0.54-1.36). Subgroups of Vietnam veterans who had higher estimated opportunities for Agent Orange exposure seemed to be at greater risk of STSs when their counterparts in Vietnam were taken as a reference group. However, this risk was not statistically significant."
  • Greenwald P et al., Sarcomas of soft tissues after Vietnam service, J Natl Cancer Inst. 1984 Nov;73(5):1107-9.
    • Abstract. "Vietnam service and military service experiences of 281 men with sarcomas of soft tissues were compared in this epidemiologic study to a control group of men derived from driver's license files and matched on 5-year period of birth and ZIP code of residence. No direct association was found for service in Vietnam (odds ratio, 0.53; confidence limits, 0.21-1.31) or for any military service (odds ratio, 0.53; confidence limits, 0.37-0.76). A multivariate matched logistic regression analysis showed similar results for Vietnam service while controlling for military service. Results also were similar when the 130 cases who had died were compared to a second control group derived from death certificates. Finally, no significant associations were found for "Agent Orange" or other variables that might be related to herbicide exposure.
  • Erickson J et al., Vietnam veterans' risks for fathering babies with birth defects, JAMA. 1984 Aug 17;252(7):903-12.
    • Abstract. "Vietnam veterans' risks for fathering babies with major structural birth defects were assessed using a case-control study. Information regarding military service in Vietnam was obtained from interviews with mothers and fathers of babies in case and control groups and from review of military records. Vietnam veterans, in general, did not have an increased risk of fathering babies with defects (all types combined; relative risk estimate, 0.97). Vietnam veterans who had greater estimated opportunities for Agent Orange exposure did not seem to be at greater risk for fathering babies with all types of defects combined. However, for a few specific types of defects the estimated risks were higher for subgroups of Vietnam veterans that may have had a greater likelihood of exposure to Agent Orange. These seemingly higher risks could be chance events, the result of some experience in the Vietnam service of the father, or the result of some other unidentified risk factor."
  • Korgeski G and Leon G, Correlates of self-reported and objectively determined exposure to Agent Orange, Am J Psychiatry. 1983 Nov;140(11):1443-9.
    • Abstract. "The authors examined the relationship between 100 Viet Nam veterans' self-reported and objectively determined exposure to the herbicide Agent Orange and the relationship between self- or objective ratings and self-reported psychological and medical problems. Veterans who believed they had been exposed reported more psychological and medical problems than the other veterans but did not differ on "success at living" indices; the medical problems many reported suggested psychosomatic etiologies. Grouped according to objective ratings of herbicide exposure, the veterans did not show such differences in psychological or medical problems. No differences on neuropsychological testing appeared, no matter how the subjects were grouped.
  • Stevens K., Agent Orange toxicity: a quantitative perspective, Hum Toxicol. 1981;1(1):31-9.
    • Abstract. "1 The minimum toxic dose of tetrachloro-dibenzo-p-dioxin (TCDD) for man has been calculated from monkey and human data to be 0.1 microgram kg-1. 2 The amount of TCDD which man takes in from his environment is about 1/2050 of that present in one square metre of his immediate environment. 3 The average concentration of TCDD present in Vietnam immediately after spraying Agent Orange was 8 microgram m-2. 4 A soldier directly sprayed would attain an internal body concentration of 7 X 10(-5) microgram kg-1 or 1/1750 of the minimum toxic dose; soldiers moving through previously sprayed areas would ingest much less. 5 These quantitative aspects indicate that the dioxin sprayed with Agent Orange in Vietnam cannot have caused systemic illnesses in Vietnam veterans or birth defects in their children."

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