Veterans and Agent Orange Update 2002 (2003) / Chapter Skim
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5. Exposure Assessment
5. Exposure Assessment
Pages 215-241
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From page 215... ...
Conclusions Strength of Evidence from Epidemiologic Studies On the basis of its evaluation of the epidemiologic evidence reviewed in this and previous Veterans and Agent Orange reports, the committee finds that there is inadequate or insufficient evidence to determine whether an association exists between exposure to the chemicals of interest (2,4-D, 2,4,5-T or its contaminant TCDD, picloram, or cacodylic acid) and melanoma.
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From page 216... ...
The strongest evidence to date comes from the medical-validation study of Australian Vietnam veterans. The estimated expected number of cases is considerably lower than the number of reported cases that were validated.
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From page 217... ...
Manne Vietnam veterans 36 0.9 (0.~1.5) a Given when available.
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From page 218... ...
of melanoma in 8.9 in Chapaevsk; 3.5 in females Samara Regionb VIETNAM VETERANS Studies Reviewed in Update 2000 AFHS, 2000 Air Force Ranch Hand veterans 16 1.8 (0.8-3.8) AIHW, 1999 Australian Vietnam veterans male 483 380 expected (342~18)
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From page 219... ...
The cohort included 261 workers exposed to phenoxy herbicides and 243 nonexposed workers. Follow-up data on the occurrence of cancer were collected in 195~1994 on mortality and in 1958-1992 on incidence.
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From page 220... ...
(20011. Conclusions Strength of Evidence from Epidemiologic Studies On the basis of its evaluation of the epidemiologic evidence reviewed in this and previous Veterans and Agent Orange reports, the committee finds that there is inadequate or insufficient evidence to determine whether an association exists between exposure to the chemicals of interest (2,4-D, 2,4,5-T or its contaminant TCDD, picloram, or cacodylic acid)
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From page 221... ...
Low herbicide exposure 33 1.9 (1.~3.6) High herbicide exposure 46 3.9 (2.2-6.9)
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From page 222... ...
Breast-cancer incidence generally increases with age. In the age groups of most Vietnam veterans, the incidence in whites is slightly higher than that in blacks.
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From page 223... ...
Most female Vietnam veterans who were potentially exposed to herbicides In Vietnam are approaching or have reached menopause and will experience an increasing risk of breast cancer. It is expected on the basis of demographics alone, therefore, that breast cancer will be a conspicuous and significant cause of death.
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From page 224... ...
This study used breast adipose tissue and hence required the use of female controls without breast cancer who had undergone breast surgery. That prevented the use of general-population controls and hence limited the external validity of the results.
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From page 225... ...
As descnbed in previous reports and elsewhere in this update, the Seveso cohortisa un~queresource for study~ngthe effect of TCDD because of an industrial explosion that occurred in the area in July 1976 and resulted in the highest TCDD concentrations known in human residential populations. The new historical cohort study differs from p revious s tudies o n t he S eveso c ohort i n u sing i ndividual TCDD concentrations as opposed to zones as indicators of exposure.
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From page 226... ...
The study was well designed and appears to have adequate power. Given the paucity of data on Vietnam veterans, the study is highly relevant for the assessment of the effect of Agent Orange and other herbicides on breast-cancer risk In Vietnam veterans.
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From page 227... ...
Therefore, on the basis of its evaluation of the epidemiologic evidence reviewed in this and previous Veterans arid Agent Orange reports, the committee finds that there is still inadequate or insufficient evidence to determine whether there is an association between exposure to the chemicals of interest (2,4-D, 2,4,5-T or its contaminant TCDD, picloram, or cacodylic acid) and risk of breast cancer.
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From page 228... ...
Chapter 3 discusses recent toxicologic studies that concern biologic plausibility. Increased Risk of Disease Among Vietnam Veterans There are no data on which to base a conclusion concerning whether Vietnam veterans are at increased risk for breast cancer because of exposure to herbicides or TCDD.
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From page 229... ...
Studies Reviewed in LAO Thomas et all, 1991 Women Vietnam veterans 17 1.2~0.~2.5) a Given when available.
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PREPUBLICATION COPY- UNCORRECTED PROOF CANCERS OF THE FEMALE REPRODUCTIVE SYSTEM This section addresses cancers of the cervix CD-9 I80.~80.9) , endometnum (also referred to as the corpus uteri; ICD-9 IS2.~82.l, I82.~3)
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From page 231... ...
(2000) report on gynecologic cancers among female Vietnam veterans.
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From page 232... ...
An analysis linking the locations of military service of these Vietnam veterans to spraying missions may make it possible to evaluate Agent Orange exposure in relation to the outcomes. Synthesis The study of female Vietnam veterans provides some evidence that female reproductive cancers namely, neoplasms of the cervix, uterus, and ovary -- - are not increased in this cohort.
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From page 233... ...
Chapter 3 discusses recent toxicologic studies that concern biologic plausibility. Increased Risk of Disease Among Vietnam Veterans The sparse data on increased risk of female reproductive cancers in Vietnam veterans come from an Australian study.
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From page 234... ...
a OCCUPATIONAL Studies Reviewed in Update 1998 Kogevinas et al., 1997 LARC cohort (includes cancers of the endometrium) 3 Studies Reviewed in MAO Blair et al., 1993 Ronco et al., 1992 Wiklund, 1983 US farmers in 23 states Whites Nonwhites Danish farmers Self-employed farmers Family workers Employees Swedish agricultural workers ENVIRONMENTAL Studies Reveiwed in Update 2000 Bertazzi et al., 2001 Seveso residents 20-year follow-up Weiderpass et al., 2000 Bertazzi et al., 1998 Zone B females Swedish females Seveso residents 15-year follow-up Zone B females Studies Reviewed in Update 1998 Bertazzi et al., 1997 Seveso residents 15-year follow-up 15 17 103 9 135 2 154 3.4 (0.7-10.0)
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From page 235... ...
VIETNAM VETERANS New Studies Kang et al., 2000 Female Vietnam veterans 41 1.0 (0.~1.6) Studies Reveiwed in Update 2000 CDVA, 1998b Australian Vietnam veterans female 4b 1 expected(0-5)
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From page 236... ...
Prostate cancer tends not to be fatal in the overwhelming majority of cases, so studies of mortality may be unable to detect an increased incidence of the disease. Findings showing an association between an exposure and prostate cancer mortality should be examined closely to determine whether the exposed group might have had poorer access to treatments that would decrease the likelihood of death.
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From page 237... ...
The pay slips of the company included information about the number of working hours or days in different work tasks and were used to construct a measure of exposure to phenoxy herbicides. The cohort was divided into two exposure groups, one with more than 5 working days of phenoxy-herbicide exposure and the other with 5 days or less.
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From page 238... ...
Differences across populations In the rate of use of PSA could alter the relationship between exposure and mortality from prostate cancer. In contrast, the study of Swedish lumberjacks does address incidence but, given the study size, yields only weak evidence that those with the highest exposures to phenoxy herbicides may have an increased risk of prostate cancer.
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From page 239... ...
Conclusions Strength of Evidence from Epidemiologic Studies On the basis of its evaluation of the epidemiologic evidence reviewed in this and previous Veterans and Agent Orange reports, the committee finds that there is limited or suggestive evidence of an association between exposure to at least one of the chemicals of interest (2,4-D, 2,4,5-T or its contaminant TCDD, picloram, or cacodylic acid) and prostate cancer.
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From page 240... ...
The statistically significant increase In prostate-carlcer SMRs for Australian Vietnam veterans suggests that US Vietnam veterans may be at increased nsk. Further follow-up that includes, in particular, studies of morbidity among living veterans would help to define He risk.
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From page 241... ...
Bertazzi et al., 1989b Seveso residents—10-year follow-up Zone B males 3 2.2 (0.7-6.9) VIETNA1\I VETERANS Studies Reviewed in Update 2000 AFHS, 2000 Air Force Ranch Hand veterans 241 26 0.7(0.4-1.3)
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