Prepared by Louise Edwards Institute of Molecular BioSciences Massey University

From July 1965 until November 1971, New Zealand Defence Force Personnel fought in the Vietnam War. During this time the United States military forces sprayed more than 76,500,000 litres of phenoxylic herbicides over parts of Southern Vietnam and Laos. The most common herbicide sprayed was known as ‘Agent Orange’. All of the Agent Orange sprayed during the Vietnam War was contaminated with 2,3,7,8tetrachlorobenzo-para-dioxin (known simply as TCDD), a known human carcinogen. Since returning to New Zealand more than 30 years ago, New Zealand Vietnam War veterans have expressed concern about the numerous health problems experienced by both themselves and their children. New Zealand Vietnam War veterans attribute these health problems to exposure to Agent Orange while serving in Vietnam. This study aimed to ascertain whether or not a small sample of New Zealand Vietnam War veterans have incurred genetic damage as a result of service in Vietnam. The Sister Chromatid Exchange assay (SCE) is a very sensitive and widely applied assay used as a bioindicator of genetic damage induced by an environmental agent or clastogen. In the current study a group of 24 New Zealand Vietnam War veterans and 23 control volunteers were compared using an SCE analysis. All participants were screened to reduce the possible influence of factors that could severely impact on findings and to eliminate any bias in the SCE results. The results from the SCE study show a highly significant difference between the mean of the experimental group and the mean of the control group (p < 0.001). This result suggests, within the strictures of interpreting the SCE assay, that this particular group of New Zealand Vietnam War veterans has been exposed to a harmful substance(s) which can cause genetic damage. Comparison with a matched control group would suggest that this can be attributed to their service in Vietnam. The result is strong and indicates that further scientific research on New Zealand Vietnam War veterans is required.