Impact of war on veteran life span: natural experiment involving combat versus non-combat exposed military personnel

Introduction: There is still uncertainty around the impact of combat exposure on the life span of war veterans. Therefore we made use of a natural experiment to study the impact on veteran life span of combat versus non-combat exposure in World War II (WW2).

Methods: The combat-exposed military personnel were derived from a random (10%) sample of the military roll of the 28th (Māori) Battalion from New Zealand. One non-combat cohort was the 15th Reinforcements of this same Battalion, since the war ended before they reached the front line. The other non-combat cohort were Māori personnel who were only involved in Jayforce, which occupied Japan at the end of the WW2. Data on life span were mainly derived from an official repository of birth and death records, but supplemented with other sources, including military files.

Results: When comparing life spans of service veterans, there was no statistically significant reduction for the average life span of the 234 combat-exposed veterans in our sample from the 28th (Māori) Battalion (66.7 years), relative to the Māori veterans from two non-combat cohorts: the 132 personnel in the 15th Reinforcements (67.2 years) and the 147 personnel in Jayforce (66.9 years).

Conclusions: Despite a very high level of wounding in the combat-exposed group (48%), there were no statistically significant reductions in life span between this group and comparable non-combat exposed veterans. This finding contrasts to life span reductions found in a similar study of New Zealand veterans of WW1.