Chapter 8 - Summary, Conclusions and Recommendations
8.1 Summary of Findings
The Korean War Veterans Mortality Study is the first study to examine the mortality of all Australian male Korean War veterans.
The study has various strengths, and given the constraints of the study design, unavoidable weaknesses that affect its interpretation.
The strengths of this study include:
- follow-up or tracing was from the end of service until 2000 - the length of time that elapsed since the veterans' service in Korea ranged from approximately 45 to 48 years;
- vital status was established for 94.9% of veterans in the study;
- the study had sufficient power to be able to detect increases of 20% in the relative risk for most of the diseases of interest; and
- it was conducted in a country with an advanced medical system where the diagnosis and coding is likely to be correct in the majority of instances.
The weaknesses of this study include:
- there was an under-ascertainment of deaths. About 5.1% of the Korean War veterans could not be located. It is expected that some of these have died prior to the establishment of the National Death Index. This possibly leads to an under-estimation of the effects of Korean War service;
- there was a lack of measurement of exposure to risk factors that might contribute to the observed associations, such as cigarette smoking, alcohol intake, hepatitis B virus infection, endemic parasites and bacteria, pesticides, solvents, chemical exposures and environmental exposures in Korea; and
- the exposure measures available were length of service and period of service in Korea. These could not reflect occupational variations or the variation in exposure to Korean service within and between the Navy, Army and Air Force.
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8.1 Summary of findings
The death rate from all causes for Korean War veterans relative to Australian males was estimated to be 1.21 (95% CI 1.18 - 1.24) These results demonstrate a 21% increase in mortality among Korean War veterans compared with the Australian male population. This increase in mortality among these veterans is continuing to occur.
Of the three Services, Army veterans experienced the highest level of mortality followed by Navy, then Air Force. Air Force veterans showed a lower mortality rate than the Australian male population.
Mortality from 13 of the 19 diseases of a priori interest was elevated. This included mortality from chronic obstructive pulmonary disease, ischaemic heart disease, stroke, alcoholic liver disease and external causes. Among the neoplasms of interest, cancer of the oesophagus, gastrointestinal and colo-rectal cancers, and head and neck, lung, genito-urinary and prostate cancers were statistically significantly increased. Mortality from two a priori diseases (tuberculosis and peptic ulcer disease) and four cancers (liver and gallbladder, mesothelioma, melanoma and leukaemia) did not differ from that of Australian males. None of the a priori diseases showed a statistically significant decrease in mortality.
In descending order, the most common causes of death overall and in each Service were from diseases of the circulatory system, neoplasms, external causes such as suicide and motor vehicle accidents, and diseases of the respiratory system. Compared to the Australian male population, Army Korean War veterans had a 31% increased mortality rate for all cause mortality and an additional 13 causes of death which were analysed.
Army veterans only showed a reduced mortality for congenital malformations and this was expected because of the recruit selection process. Navy veterans experienced an 11% overall increased mortality rate with an increase in mortality from neoplasms, circulatory diseases, stroke and chronic obstructive pulmonary disease. Navy veterans had a reduced mortality for four of the 27 causes of death. Air Force veterans had an 11% decreased mortality overall and demonstrated a lower mortality rate for three of the causes of death which were analysed.
Mortality from specific cancers was investigated in detail. Overall, there was a 31% elevated mortality from neoplasm for all Korean War veterans. The most frequently occurring cancer deaths in descending frequency were from lung, gastrointestinal, genito-urinary, head and neck, oesophagus, and larynx and these cancer mortality rates were all significantly elevated compared to the Australian male population.
The most common deaths from cancer in the Navy and Army were similar to those of all Korean War veterans. However, in the Air Force, genito-urinary cancers were more common than gastrointestinal cancers.
In the Navy, elevated mortality rates were found for lung, genito-urinary, and head and neck cancers, while death from lymphoid leukaemia was lower than the Australian male population. Elevated mortality rates were found in the Army for deaths from gastrointestinal, colo-rectal, head and neck, larynx, liver and gallbladder, lung, and oesophageal cancers, and those cancers of unknown primary site. Only mesothelioma had a reduced mortality rate. Among Air Force veterans, only prostate cancer was elevated. Two cancers categories, liver and gallbladder cancer, and stomach cancer, showed a lower mortality rate among Air Force veterans.
Many cancers for which there was elevated mortality among the Korean War veterans are cancers associated with smoking. Modelling suggested that smoking rates well in excess of community levels were required to explain these increases, and may not account for all of the increase. However, in the absence of information about the percentage of veterans who smoked and the numbers of cigarettes smoked per day, it is not possible to determine precisely how much of the excess could be attributed to smoking.
Alcohol related deaths are also increased, and this may be an effect of both lifestyle and post traumatic stress disorder.
Given the absence of quantitative data on exposure to occupational and environmental hazards, the effects of duration of service and the period of service in Korea were investigated for Navy and Army veterans. The number of Air Force veterans were too small for this analysis. Mortality by duration of service in Korea for Navy and Army veterans did not show any clear pattern between the different duration categories or within each Service branch.
Investigating mortality by period of service among Army veterans reveals that those who completed their Korean service prior to 1952 (the offensive / counter-offensive phase of the conflict), had a significantly lower mortality rate from suicide compared to the Australian male community. Those who served in Korea after 1952 had a higher mortality from suicide compared to the community norm. Apart from this unexpected and possibly chance post hoc finding, there was little evidence of any other trend from the effect of Korean service.
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Overall, Korean War veterans have a 21% increase in all cause mortality compared to Australian males with an elevation in 12 of the 18 a priori diseases of interest. Deaths from cancer were elevated by 31%. Mortality was highest in Army veterans and lowest in Air Force veterans.
Because of the limitation in measurement of factors known to affect mortality, their contribution to the increase in mortality could not be determined. Some of the diseases with higher mortality rates have been linked with cigarette smoking. Although Korean War veterans have a higher mortality for several causes of death that have been identified, there is no way of determining whether this resulted from some exposure in Korea or whether it was the result of lifestyle changes arising as a consequence of Korean War service or a combination of both.
1. The Korean War has been referred to as 'The Forgotten War' 1. This study has demonstrated that participation in the Korean War is associated with an overall increase in mortality of 21% and an increase in cancer mortality of 31%. This increase in mortality is continuing. About 50% of all Korean War veterans are still alive. In light of the demonstrated increase in mortality consideration should be given to targeted health interventions for the surviving Korean War veterans.
2. This mortality study should not be considered in isolation, but with the companion studies that are being undertaken simultaneously. Thus, this study and the companion cancer incidence study should be referred to the Scientific Advisory Committee oversighting the health study of surviving Korean War veterans, as these studies may indicate additional areas to address in the health survey.
3. There is anecdotal evidence that Australian veterans of the Korean War smoked more than the comparable Australian population. A health survey of surviving veterans of the Korean War is about to commence. It is recommended that the level of cigarette consumption in the survivors be assessed and that the current survey of veterans of the Korean War include questions on current smoking. This may allow programs of smoking cessation to be more effective and to be better targeted within the Korean War veterans.
4. Similarly, the increase in mortality from alcoholic liver disease indicates that the level of alcohol consumption be assessed in the health survey of survivors. This may allow programs aimed at reducing alcohol intake to be better targeted within the surviving Korean War veterans.
5. The information from the current study, including the date when each veteran was last known to be alive or dead, should be stored safely together with the nominal roll. Updated vital status data should be stored separately and this information made available for the general health survey of surviving Korean War veterans.
6. In this study there was considerable difficulty in locating some veterans. Some of this difficulty was due to errors in recording client data in the DVA database and matching against Defence records. DVA should liaise with Defence to ascertain methods of improving matching against Defence personnel records. This should be of longer term benefit in conducting studies of cohorts of veteran populations and may lead to improvement in quality control systems on data entry.
- Korean War .net, website: http://www.koreanwar.net/why.htm