Chapter 4 - Characteristics of the study cohort
4.1 Birth Year Distribution of Veterans
4.2 Age at First Service in Korea
4.3 Nature of Service in Korea
4.3.1 Total days in Korea
4.3.2 Tours and visits to Korea
4.4 Involvement in other conflicts
4.4.1 Involvement in the Vietnam War
4.4.2 Involvement in World War II
4.4.3 Compensation claims attributed to Korean War service
4.5 Summary
References
This chapter describes in more detail the demographics and nature of service in Korea of the study cohort during the Korean War.
4.1 Birth year distribution of veterans
The birth year distribution of Korean War veterans on the Nominal Roll is illustrated in the histogram below (Figure 4-1). It is skewed to the left with most birth years clustered between 1920 and 1935. The median year of birth is 1928.
Figure 4-1: Number of Korean War veterans by year of birth
Note: Year of birth data were missing for 20 male Korean War veterans.
4.2 Age at first service in Korea
Using data for year of first service in Korea and year of birth for each veteran, the following descriptive statistics relating to age at first service in Korea, shown in Table 4-1, were obtained. Data were missing for six Navy veterans, 25 Army veterans and two Air Force veterans.
| Table 4-1: Age in years at first service in Korea - descriptive statistics | |||||
|---|---|---|---|---|---|
| Group | Range | Mean | Std dev | Median | Mode |
| Navy | 15-51 | 23.7 | 4.5 | 23 | 23 |
| Army | 14-59 | 24.9 | 5.5 | 24 | 22 |
| Air Force | 18-54 | 26.6 | 6.5 | 25 | 24 |
These data show that, overall, Service personnel were generally young when they first served in Korea. The Navy was the youngest group and the Air Force was the oldest group when they first served in Korea.
4.3 Nature of service in Korea
To explore whether the death rates of veterans vary according to the duration or type of service, a number of measures of the nature of service in Korea were available. The duration of Korean service measures were: total days in Korea; total number of tours; and total number of visits. Each of these measures is described below.
4.3.1 Total days in Korea
Complete data were only available for 17,853 of the 17,871 personnel. Data were missing for three Navy veterans, 13 Army veterans and two Air Force veterans. Using data for the start and end date for each period of service in Korea for each veteran, the following descriptive statistics relating to the total number of days in Korea, shown in Table 4-2, were obtained.
| Table 4-2: Number of days in Korea - descriptive statistics | |||||
|---|---|---|---|---|---|
| Group | Range | Mean | Std dev | Median | Mode |
| Navy | 7-880 | 249 | 108 | 219 | 176 |
| Army | 1-1467 | 305 | 158 | 346 | 386 |
| Air Force | 1-1161 | 145 | 123 | 123 | 33 |
Table 4-3 shows the number of personnel, grouped by branch of Service and the total number of days served in Korea. This data is displayed graphically in Figures 4-2 to 4-4 and shows the marked differences in the length of duty in the three Services. Whereas almost all Army personnel served approximately one year, the majority of Navy personnel served between five to 10 months and Air Force personnel for less than five months.
| Table 4-3: Total number of days in Koreaa | ||||||
|---|---|---|---|---|---|---|
| Days | Navy | Army | Air Force | |||
| Number | % | Number | % | Number | % | |
| 1-50 | 26 | 0.5 | 672 | 6.2 | 327 | 26.7 |
| 51-100 | 326 | 5.6 | 716 | 6.6 | 165 | 13.5 |
| 101-150 | 98 | 1.7 | 670 | 6.2 | 274 | 22.4 |
| 151-200 | 1,355 | 23.5 | 525 | 4.8 | 129 | 10.5 |
| 201-250 | 1,547 | 26.8 | 645 | 5.9 | 124 | 10.1 |
| 251-300 | 1,424 | 24.7 | 827 | 7.6 | 108 | 8.8 |
| 301-350 | 203 | 3.5 | 1,632 | 15.0 | 30 | 2.5 |
| 351-400 | 362 | 6.3 | 4,013 | 37.0 | 16 | 1.3 |
| 401-450 | 115 | 2.0 | 320 | 2.9 | 15 | 1.2 |
| 451-500 | 74 | 1.3 | 136 | 1.3 | 11 | 0.9 |
| 501-550 | 77 | 1.3 | 128 | 1.2 | 9 | 0.7 |
| 551-600 | 65 | 1.1 | 128 | 1.2 | 6 | 0.5 |
| > 600 | 100 | 1.7 | 445 | 4.1 | 10 | 0.8 |
| Total | 5,772 | 100 | 10,857 | 100 | 1224 | 100 |
| a Includes 37 females and 16 members of philanthropic organisations Note: Column totals may not add up to 100% due to rounding. |
||||||
Figure 4-2: Navy service in Korea
Figure 4-3: Army service in Korea
Figure 4-4: Air Force service in Korea
Table 4-4 shows the number of females, grouped by branch of Service and the total number of days served in Korea.
| Table 4-4: Total number of days in Korea (females) | ||||
|---|---|---|---|---|
| Days | Armya | Air Force | ||
| Number | % | Number | % | |
| 1-50 | 8 |
21.6 |
13 |
61.9 |
| 51-100 | 19 |
51.4 |
5 |
23.8 |
| 101-150 | 6 |
16.2 |
1 |
4.8 |
| 151-200 | 3 |
8.1 |
||
| 201-250 | ||||
| 251-300 | 1 |
4.8 |
||
| 301-350 | ||||
| 351-400 | ||||
| 401-450 | 1 |
2.7 |
1 |
4.8 |
| 451-500 | ||||
| 501-550 | ||||
| 551-600 | ||||
| > 600 | ||||
| Total | 37 |
100 | 21 | 100 |
| a Includes 3 members of philanthropic organisations Note: Column totals may not add up to 100% due to rounding. |
||||
4.3.2 Tours and visits to Korea
Tables 4-5 to 4-8 show the total number of tours and the total number of visits undertaken by Navy, Army and Air Force veterans, and for the civilian groups - war correspondents and photographers. The Army personnel include 16 men from philanthropic organisations.
For the purposes of this study, a visit is defined as service of less than 28 consecutive days on land in Korea or on ships operating off the Korean coast. In contrast, a tour is defined as service equal to or more than 28 consecutive days on land in Korea or in ships operating off the Korean coast.
Navy Korean War veterans
Table 4-5 shows that this cohort is composed of a reasonably homogenous group. Most Navy personnel (84.7%) completed one tour and 99.8% performed one or more tours. The average number of days spent on land in Korea or in Korean waters by Navy personnel was 249 days.
| Table 4-5: Service characteristics of Navy Korean War veterans | |||||||
|---|---|---|---|---|---|---|---|
| Number of visits | |||||||
| Number of tours | 0 | 1 | 2 | 3 | over 3 | Total | % |
| 0 | 8 | 1 | 9 | 0.2 | |||
| 1 | 4,836 | 50 | 3 | 4,889 | 84.7 | ||
| 2 | 784 | 7 | 1 | 792 | 13.7 | ||
| 3 | 72 | 4 | 1 | 77 | 1.3 | ||
| Over 3 | 4 | 1 | 5 | 0.1 | |||
| Total | 5,696 | 70 | 6 | 5,772 | 100.0 | ||
| % | 98.7 | 1.2 | 0.1 | 0.0 | 0.0 | 100.0 | |
| Note: Column and row totals may not add up to 100% due to rounding. | |||||||
Army Korean War veterans
Table 4-6 shows that approximately 77% of Army personnel undertook one tour of duty and no visits during their service in Korea. Only 15.3% undertook two or more tours of duty, while 4.3% carried out visits but did not undertake a tour of duty. The average total number of days of service for veterans was 305 days.
| Table 4-6: Service characteristics of Army Korean War veteransa | |||||||
|---|---|---|---|---|---|---|---|
Number of visits
|
|||||||
| Number of tours | 0 | 1 | 2 | 3 | over 3 | Total | % |
| 0 | 278 | 68 | 119 | 1 | 466 | 4.3 | |
| 1 | 8,325 | 336 | 62 | 1 | 1 | 8,725 | 80.4 |
| 2 | 1,324 | 108 | 0 | 1 | 0 | 1,433 | 13.2 |
| 3 | 228 | 2 | 1 | 0 | 0 | 231 | 2.1 |
| over 3 | 2 | 2 | 0.0 | ||||
| Total | 9,879 | 724 | 131 | 121 | 2 | 10,857 | 100.0 |
| % | 91.0 | 6.7 | 1.2 | 1.1 | 0.0 | 100.0 | |
|
a Includes 37 females and 16 members of philanthropic organisations. Note: Column and row totals may not add up to 100% due to rounding. |
|||||||
Air Force Korean War veterans
Table 4-7 presents the service characteristics of Air Force Korean War veterans.
Overall, 57.4% of Air Force personnel conducted one tour of duty in Korea. Only 25.1% conducted two or more tours of duty. The average duration of service for Air Force personnel was 145 days. A large number of visits were completed by Air Force personnel reflecting the operational transport role including aeromedical evacuation.
| Table 4-7: Service characteristics of Air Force Korean War veteransa | |||||||
|---|---|---|---|---|---|---|---|
| Number of visitsb | |||||||
| Number of tours | 0 | 1 | 2 | 3 | over 3 | Total | % |
| 0 | 103 | 40 | 25 | 46 | 214 | 17.5 | |
| 1 | 533 | 101 | 34 | 17 | 17 | 702 | 57.4 |
| 2 | 156 | 38 | 16 | 9 | 13 | 232 | 19.0 |
| 3 | 25 | 13 | 8 | 3 | 6 | 55 | 4.5 |
| Over 3 | 5 | 6 | 4 | 3 | 2 | 20 | 1.6 |
| Total | 719 | 261 | 102 | 57 | 84 | 1223 | 100.0 |
| % | 58.8 | 21.3 | 8.3 | 4.7 | 6.9 | 100.0 | |
|
a Includes 21 females b Aeromedical evacuation flights are included Note: Column and row totals may not add up to 100% due to rounding. |
|||||||
Females
Table 4-8 displays the service characteristics for females who served in Korea. There were 34 females in the Army, 21 in the Air Force and three with the Australian Red Cross. Only six Air Force females completed one tour or more, in contrast to Army females, of whom 31 completed one tour or more. The frequent visits reflect the aeromedical evacuation duties of Air Force nurses. One Air Force female completed 54 aeromedical evacuation flights.
| Table 4-8: Service characteristics of females | |||||||
|---|---|---|---|---|---|---|---|
| Number of visits | |||||||
| Number of tours | 0 | 1 | 2 | 3-20 | over 20 | Total | % |
| 0 | 4 | 4 | 6 | 6 | 20 | 34.5 | |
| 1 | 30 | 1 | 1 | 1 | 33 | 56.9 | |
| 2 | 3 | 3 | 5.2 | ||||
| 3 | 2 | 2 | 3.4 | ||||
| Total | 35 | 5 | 5 | 7 | 6 | 58 | 100.0 |
| % | 60.3 | 8.6 | 8.6 | 12.1 | 10.3 | 100.0 | |
| Note: Column and row totals may not add up to 100% due to rounding. | |||||||
4.4 Involvement in other conflicts
One issue that arose during the study was whether any results might reflect involvement in conflicts other than the Korean War. In particular, the Vietnam Veterans Mortality Study 1 showed an increased mortality from involvement in that conflict. Accordingly, the Nominal Roll was matched against the Vietnam Veterans Nominal Roll and also against the DVA compensation claims database to estimate the participation rates of Korean War veterans in both World War II and the Vietnam War.
4.4.1 Involvement in the Vietnam War
Matching of the Korean Veterans Nominal Roll against the Vietnam Veterans Nominal Roll revealed that 1,562 (8.7%) Korean War veterans participated in the Vietnam War. Exploration of the DVA compensation claims database revealed that 1,462 Korean War veterans had submitted claims that they attributed to the Vietnam War. As DVA only has files on 81% of all Korean War veterans, this number was expected to be an under-estimate.
4.4.2 Involvement in World War II
Matching of the Nominal Roll against the developing World War II Nominal Roll was not feasible during the study. Exploration of the DVA compensation claims database revealed that 5,270 (29.5%) Korean War veterans had submitted claims that they attributed to their World War II service, and this is likely to be an under-estimate.
4.4.3 Compensation claims attributed to Korean War service
In contrast to involvement in the Vietnam War and World War II, 13,460 (75.3%) of Korean War veterans had submitted claims that they attributed to their service in Korea.
4.5 Summary
The nature of service in Korea varied considerably between the Navy, Army and Air Force. Navy personnel spent an average of 249 days in Korean waters with 85% completing one tour only. Army personnel averaged 305 days in Korea with 77% completing one tour only. In contrast, only 57% of Air Force personnel completed one tour only, with an average duration of service of 145 days. The large number of visits conducted by Air Force personnel reflects the operational transport role including aeromedical evacuation.
Almost 9% of Korean War veterans participated in the Vietnam War and compensation claims indicate that at least 30% of Korean War veterans participated in World War II.
Involvement in other conflicts may result in an increase or decrease in health outcomes depending on the circumstances. Whether involvement in the Vietnam War or World War II increases or decreases mortality among Korean War veterans requires further investigation.
The nature of service and involvement in other conflicts need to be taken into consideration when interpreting the results.