Mortality among Australian conscripts of the Vietnam conflict era. II. Causes of death.

In a cohort of Australian national service conscripts, death rates from International Classification of Diseases, Eighth Revision (ICD-8) cause of death classes for 19,205 veterans of the Vietnam conflict were compared with those of 25,677 veterans who served only in Australia. Comprehensive, clinically reviewed cause of death data were collected and coded to a single ICD-8 three-digit cause of death code by the Australian Bureau of Statistics. Over 98% of the deaths among veterans were included in five classes of causes of death. These were neoplasms (14%), diseases of the circulatory system (7%), accidents, poisonings, and violence (external causes) (74%), and diseases of the digestive system and mental disorders (2% each). For the last two classes, chronic abuse of alcohol was a common factor in most deaths among Vietnam veterans. The death rates of Vietnam veterans were statistically significantly higher than those for other veterans for only two classes of causes of death: diseases of the digestive system and external causes. After adjustment for Army corps grouping, this excess was not statistically significant for external causes. There was no statistically significant difference in death rates from neoplasms, nor were deaths from specific neoplasms more frequent among the group that served in Vietnam. While this suggests that service in the Vietnam conflict has not increased death rates from neoplasms among servicemen, the follow-up period, ranging from 9-16 years, is shorter than the latency period for some neoplasms. The study findings provide a measure of support for claims by Australian Vietnam veterans of an increased incidence of stress-related disorders associated with service in the Vietnam conflict.