Consanguinity, Epidemics and Early Life Survival in Colonial Quebec, 1720-1830

Jessica Gagnon-Sénat, Université de Montréal
Alain Gagnon, Université de Montréal
Lisa Dillon, Université de Montréal

Inevitably, consanguinity accumulated over time in Colonial Quebec. Concurrently, Quebec was the victim of several epidemics. The aim of this study is to evaluate the relationship between child mortality and consanguinity in epidemic periods of Colonial Quebec between 1720 and 1830. On the one hand, it is hypothesized that children with homologous genes on many loci would have a significantly higher mortality rate compared to non consanguineous children, due to homozygote disadvantage. On the other hand, consanguineous individuals may have a more favourable survival because of the effect of settlement present in the measure of consanguinity. Cox regression models allow us to explore and partially disentangle the roles of genetic and environmental factors. Immigrants, multiple births and individuals lacking a genealogy from the Registre de population du Québec ancien (RPQA) and Infrastructure intégrée des microdonnées historiques de la Population du Québec (IMPQ) are excluded. Altogether, 610,412 individuals are analysed in the Cox models that signal an unfavourable survival of consanguineous, especially close consanguineous, individuals during epidemics. However, underlying effects such as selection processes and unrobust settlement controls guide the results of the interaction between epidemics and consanguinity, so the premise remains to be validated.

Keywords: Event history analysis, Mortality, Biodemography and genetics

See extended abstract.

  Presented in Session 29. Consequences of Pandemics: Lessons from History