SP6-41 Descriptive epidemiology of mortality among the New Zealand expeditionary forces in World War I

IntroductionThe military personnel in the New Zealand (NZ) Expeditionary Forces (NZEF) during World War I experienced high mortality (18 000+ deaths). There is little research on these deaths so we aimed to provide a more detailed historical and epidemiological account of this mortality burden.MethodsVarious NZEF datasets and sources were used to examine mortality patterns and the robustness of the available data with historical accounts. Extensive coding work was required to allow epidemiological analyses.ResultsThe majority of NZEF deaths (80.9%) were a direct result of being killed in battle or being wounded. Deaths from disease also represented a substantial NZEF loss of life (at 17.9% of all deaths). The majority of these disease deaths were from pandemic influenza but other outbreaks occurred (eg, dysentery, measles). Māori (indigenous New Zealanders) and Pacific peoples in the NZEF experienced significantly higher mortality rates from disease compared to European/Other NZEF. Healthcare workers experienced significantly lower mortality from all causes, including disease, compared to other military units. This difference is possibly the result of less frontline presence and perhaps prior immunity from occupationally-related exposure to infectious agents.ConclusionsThis study found substantial variation in mortality rates, by time, place and person. Both military factors and a pandemic played important roles in the mortality burden. The datasets based on archival sources provide a rich foundation for both historical and epidemiological research of the mortality burden among these military personnel during World War I.