Discussion Paper No. 08-05


Frontier populations provide exceptional opportunities to test the hypothesis of a trade‐off between fertility and longevity. In such populations, mechanisms favoring reproduction usually find fertile ground, and if these mechanisms reduce the chances for survival in old age, demographers should observe higher post‐reproductive mortality rates among highly fertile women. We test this hypothesis using complete female reproductive histories from three large demographic databases: the Registre de la population du Québec ancien (Université de Montréal), which covers the first centuries of settlement in Quebec; the BALSAC database (Université du Québec à Chicoutimi), including comprehensive records for the region of Saguenay‐Lac‐St‐Jean (SLSJ) in the 19th and 20th centuries; and the Utah Population Database (University of Utah), including all individuals who experienced a vital event on the Mormon Trail since the early 1800s. From these databases, we extracted, respectively, 5447, 1610, and 11395 women who survived married to age 50. Together, the three samples allow for comparisons over time (Old Quebec versus more recent Quebec and Utah) and space (Quebec versus Utah), and represent the largest data collection used to assess the impact of female reproduction on post‐reproductive survival in a natural fertility context. Using survival analyses controlling for observed and unobserved factors we found a negative influence of parity and a positive influence of age at last child on post‐reproductive survival in the three populations, with remarkably similar effect sizes in the three samples. However, we found little evidence of early fertility effects. We used Heckman’s two‐stage procedure to assess the impact of mortality selection during reproductive years, with no appreciable alteration of the main results. We conclude our empirical investigation by discussing the needs and the advantages of collaborative and comparative approaches.