U.S. Blue Water Navy Veterans of the Vietnam War: Comparisons from the Vietnam Era Health Retrospective Observational Study (VE-HEROeS).

Background: US Vietnam War Blue Water Navy veterans (BWN) conducted military operations on Vietnam's offshore waters and likely experienced various war-related exposures. The overall health of the BWN has never been systematically studied. Purpose: Describe and compare BWN's health with other servicemembers and non-veterans of the Vietnam era. Materials and methods: Survey of 45 067 randomly selected US Vietnam War theatre and non-theatre veterans and 6885 non-veterans. Results: For 22 646 male respondents, self-reported health was contrasted by veteran status defined as BWN (n=985), theatre veterans (n=6717), non-theatre veterans (n=10 698) and non-veterans (n=4246). Exposure was service in the Vietnam War theatre. Collected were demographics, military service characteristics, lifestyle factors and health conditions. Adjusted odds ratios (aOR) were calculated using multivariable logistic regression. Controlling for cigarette smoking and other covariates, respiratory cancer risk was highest in BWN vs other veterans (theatre: aOR 1.65; 95% CI 1.09, 2.50; non-theatre: aOR 1.77; 1.13, 2.77) and to non-veterans (aOR 1.78; 1.15, 2.74). Other findings showed BWN's health risks between theatre and non-theatre veterans. Conclusion: There was a higher risk for respiratory cancers in BWN. Other risks were less than theatre veterans but greater than non-theatre or non-veterans, indicating a potential role of military exposures in BWN's health.

Serum dioxin and peripheral neuropathy in veterans of Operation Ranch Hand.

We studied whether exposure to Agent Orange and its contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin), during the Vietnam War is related to peripheral neuropathy. The index subjects were veterans of Operation Ranch Hand, the unit responsible for aerial herbicide spraying in Vietnam from 1962 to 1971. We report peripheral nerve function assessed in 1982, 1985, 1987, 1992 and 1997, nerve conduction velocities measured in 1982, and vibrotactile thresholds of the great toes measured in 1992 and 1997. We assigned each Ranch Hand veteran to one of three exposure categories named "background", "low" and "high", based on his serum dioxin level. Other than the bilateral vibrotactile abnormalities, we consistently found a statistically significant increased risk of all indices of peripheral neuropathy among Ranch Hand veterans in the high exposure category in 1997, and a statistically significant increased risk of diagnosed peripheral neuropathy, incorporating bilateral vibrotactile abnormalities of the great toes, in the high category in 1992. Restricting to the enlisted veterans did not alter these results. Cautious interpretation of these results is appropriate until the relationship between pre-clinical diabetes mellitus and peripheral neuropathy is further evaluated in future examinations.

Serum dioxin and cognitive functioning among veterans of Operation Ranch Hand.

We used the Halstead-Reitan neuropsychological test battery, the Wechsler adult intelligence scale-revised, the Wechsler memory scale, and the wide range achievement test to assess cognitive functioning among Air Force veterans exposed to Agent Orange and its contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin), during the Vietnam war The index subjects were veterans of Operation Ranch Hand (N = 937), the unit responsible for aerial herbicide spraying in Vietnam from 1962 to 1971. A comparison group of other Air Force veterans (N= 1,052), who served in Southeast Asia during the same period but were not involved with spraying herbicides served as referents. Cognitive functioning was assessed in 1982, and dioxin levels were measured in 1987 and 1992. We assigned each Ranch Hand veteran to the background, low, or high dioxin exposure category on the basis of a measurement of dioxin body burden. Although we found no global effect of dioxin exposure on cognitive functioning, we did find that several measures of memory functioning were decreased among veterans with the highest dioxin exposure. These results became more distinct when we restricted the analysis to enlisted personnel, the subgroup with the highest dioxin levels. An analysis based on dioxin quintiles in the combined cohort produced consistent results, with veterans in the fifth quintile exhibiting reduced verbal memory function. Although statistically significant, these differences were relatively small and of uncertain clinical significance.

Relation of serum 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) level to hematological examination results in veterans of Operation Ranch Hand.

The authors studied indices of hematologic function and exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in Vietnam War veterans of Operation Ranch Hand--the Air Force unit responsible for the aerial spraying of Agent Orange and other herbicides in Vietnam. The herbicides were contaminated with TCDD. The authors measured TCDD serum levels in 1987 or later and extrapolated the result to the time of service in Vietnam. The authors studied serum TCDD level in relation to red blood cell count, hemoglobin, hematocrit, mean corpuscular volume, white blood cell count, platelet count, and erythrocyte sedimentation rate at each of 4 physical examinations. Compared with veterans not involved in Operation Ranch Hand, those with the highest TCDD levels in Operation Ranch Hand had mean corpuscular volumes that were about 1% higher and platelet counts that were about 4% higher. These small increases were unlikely to be of clinical significance and may not have been caused by TCDD.

Serum dioxin, insulin, fasting glucose, and sex hormone-binding globulin in veterans of Operation Ranch Hand.

We studied insulin, fasting glucose, and sex hormone-binding globulin (SHBG) in Air Force veterans exposed to Agent Orange and its contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin), during the Vietnam War. The index subjects were veterans of Operation Ranch Hand, the unit responsible for aerial herbicide spraying in Vietnam from 1962-1971. Other Air Force veterans who served in Southeast Asia during the same period but were not involved with spraying herbicides served as comparisons. We assigned each Ranch Hand veteran based on his dioxin level to one of three exposure categories, named background, low, and high. Among nondiabetic veterans, we found the mean of the logarithm of insulin significantly increased in the high dioxin category. Additionally, in nondiabetic veterans the relation between SHBG and insulin interacted significantly with dioxin category on the log scale within strata defined by age and percent body fat. Among young (age, < or = 53 yr), lean (percent body fat, < or = 25%) nondiabetic veterans in the high category, the slope relating the logarithm of SHBG and the logarithm of insulin was significantly decreased. These findings suggest a compensatory metabolic relationship between dioxin and insulin regulation.

Postservice mortality of US Air Force veterans occupationally exposed to herbicides in Vietnam: 15-year follow-up.

The US Air Force continues to assess the mortality of veterans of Operation Ranch Hand, the unit responsible for aerially spraying herbicides in Vietnam. The authors of this study found that the cumulative all-cause mortality experience of these veterans was not different from that expected (standardized mortality ratio (SMR) = 1.0). Overall, cause-specific mortality did not differ from that expected regarding deaths from accidents, cancer, or circulatory system diseases, but the authors found that there was an increased number of deaths due to digestive diseases (SMR = 1.7, 95% confidence interval (CI) 0.9-3.2). When analyzing by military occupation, they found an increase in the number of deaths caused by circulatory system diseases (SMR = 1.5, 95% CI 1.0-2.2) among enlisted ground personnel, the subgroup with the highest dioxin levels. Most of the increase in the number of deaths from digestive diseases was caused by chronic liver disease and cirrhosis, and more than half of the increase in the number of deaths from circulatory system diseases was a result of atherosclerotic heart disease. In the subgroup of Ranch Hand veterans who had survived more than 20 years since their military service in Southeast Asia, the authors found no significant increase in the risk of death due to cancer at all sites (SMR = 1.1) and a nonsignificant increase in the number of deaths due to cancers of the bronchus and lung (SMR = 1.3).