Individual determinants of mortality during the Belgian 1918 flu pandemic

Bourguignon, Mélanie [UCL] Eggerickx, Thierry [UCL] Job, Timothée Sanderson, Jean-Paul [UCL] Dauw, Ilona [UCL] Debruyne, Emmanuel [UCL] Devos, Isabelle Vrielinck, Sven et al.[show all]

In Belgium, the 1918-1919 flu period generated around 50.000 additional deaths. However, these estimations are uncertain because of the war context (generating excess mortality related to violence and other diseases and forced displacement of populations) and the lack of cause-of-death data. This communication tries to identify the individual mortality determinants associated with the 1918 flu pandemic. Who died during the flu period? Is this pandemic mortality socially neutral? Did the aggregated characteristics of the living areas (level of excess mortality, socio-professional structure and the military regime) impact the individual probability of dying during the pandemic? The analyses are based on an individual-level database from death registers: almost 60.000 deaths all causes occurring in 1918-1919 and the reference period 1912-1913 in ca. 30 Belgian municipalities. The municipalities were selected to ensure diversity in terms of geography (municipalities from each province), type of environment (rural, urban, industrial), and the level of excess mortality. Regression models estimate the individual probability of dying between October and December (months with high excess mortality related to the flu), versus the probability of dying during the other months of the year. Models are compared, first for the year 1918 and second for the years 1912-1913.