The aim of this study was to investigate the association between Vietnam experience including exposure to military herbicides and cancer incidence in Korean Vietnam War veterans.
The cancer cases of 185 265 Vietnam veterans from January 1, 1992 to December 31, 2003 were confirmed from the Korea National Cancer Incidence Database. The age-adjusted incidence and standardized incidence ratios (SIRs) were calculated using the male population during 1992 to 2003 as a standard population.
The age-adjusted overall cancer incidence per 100 000 person-years was 455.3 in Vietnam veterans. The overall cancer incidence was slightly yet significantly lower in veterans (SIR, 0.97; 95% confidence interval, 0.95 to 0.99) than in the general population. The overall cancer incidence in enlisted soldiers was not lower (SIR, 1.00), whereas that in officers was significantly lower (SIR, 0.87) than in the general population. The incidences of prostate cancer and T-cell lymphoma in all veterans, and lung cancer and bladder cancer in enlisted soldiers, and colon cancer and kidney cancer in non-commissioned officers, and colon cancer, kidney cancer, and prostate cancer in officers, were higher than in the general population. The SIR for overall cancer among Vietnam veterans rose from 0.92 for 1992-1997 to 0.99 for 1998-2003.
The overall cancer incidence in Vietnam veterans was not higher than in the general male population. Vietnam veterans and military rank subcohorts experienced a higher incidence of several cancers, including prostate cancer, T-cell lymphoma, lung cancer, bladder cancer, kidney cancer, and colon cancer than the general population. The SIR for overall cancer increased over time in Vietnam veterans.
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The aim of this study was to examine the levels of serum 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and evaluate their association with age, body mass index, smoking, military record-based variables, and estimated exposure to Agent Orange in Korean Vietnam veterans.
Serum levels of TCDD were analyzed in 102 Vietnam veterans. Information on age, body mass index, and smoking status were obtained from a self-reported questionnaire. The perceived exposure was assessed by a 6-item questionnaire. Two proximity-based exposures were constructed by division/brigade level and battalion/company level unit information using the Stellman exposure opportunity index model.
The mean and median of serum TCDD levels was 1.2 parts per trillion (ppt) and 0.9 ppt, respectively. Only 2 Vietnam veterans had elevated levels of TCDD (>10 ppt). The levels of TCDD did not tend to increase with the likelihood of exposure to Agent Orange, as estimated from either proximity-based exposure or perceived self-reported exposure. The serum TCDD levels were not significantly different according to military unit, year of first deployment, duration of deployment, military rank, age, body mass index, and smoking status.
The average serum TCDD levels in the Korean Vietnam veterans were lower than those reported for other occupationally or environmentally exposed groups and US Vietnam veterans, and their use as an objective marker of Agent Orange exposure may have some limitations. The unit of deployment, duration of deployment, year of first deployment, military rank, perceived self-reported exposure, and proximity-based exposure to Agent Orange were not associated with TCDD levels in Korean Vietnam veterans. Age, body mass index and smoking also were not associated with TCDD levels.
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The aim of this study was to evaluate the association between Agent Orange exposure and self-reported diseases in Korean Vietnam veterans.
A postal survey of 114 562 Vietnam veterans was conducted. The perceived exposure to Agent Orange was assessed by a 6-item questionnaire. Two proximity-based Agent Orange exposure indices were constructed using division/brigade-level and battalion/company-level unit information. Adjusted odds ratios (ORs) for age and other confounders were calculated using a logistic regression model.
The prevalence of all self-reported diseases showed monotonically increasing trends as the levels of perceived self-reported exposure increased. The ORs for colon cancer (OR, 1.13), leukemia (OR, 1.56), hypertension (OR, 1.03), peripheral vasculopathy (OR, 1.07), enterocolitis (OR, 1.07), peripheral neuropathy (OR, 1.07), multiple nerve palsy (OR, 1.14), multiple sclerosis (OR, 1.24), skin diseases (OR, 1.05), psychotic diseases (OR, 1.07) and lipidemia (OR, 1.05) were significantly elevated for the high exposure group in the division/brigade-level proximity-based exposure analysis, compared to the low exposure group. The ORs for cerebral infarction (OR, 1.08), chronic bronchitis (OR, 1.05), multiple nerve palsy (OR, 1.07), multiple sclerosis (OR, 1.16), skin diseases (OR, 1.05), and lipidemia (OR, 1.05) were significantly elevated for the high exposure group in the battalion/company-level analysis.
Korean Vietnam veterans with high exposure to Agent Orange experienced a higher prevalence of several self-reported chronic diseases compared to those with low exposure by proximity-based exposure assessment. The strong positive associations between perceived self-reported exposure and all self-reported diseases should be evaluated with discretion because the likelihood of reporting diseases was directly related to the perceived intensity of Agent Orange exposure.
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