Is There a Trade-Off between Fertility and Longevity? A Comparative Study of Three Large Historical Demographic Databases Accounting for Mortality Selection

Alain Gagnon, University of Western Ontario
Ken R. Smith, University of Utah
Marc Tremblay, Université du Québec à Chicoutimi
Hélène Vézina, Université du Québec à Chicoutimi
Paul-Phillipe Paré, University of Western Ontario
Bertrand Desjardins, Université de Montréal

Frontier populations provide exceptional opportunities to test the hypothesis of a trade-off between fertility and longevity. We test this hypothesis using complete female reproductive histories from three large demographic databases: the Registre de la population du Québec ancien, the Bas-du-Fleuve, Lac St-Jean, Saguenay, and Charlevoix, Chibougamou, and Côte-Nord database, and the Utah Population Database. From these databases, we extracted, respectively: 5,447, 1,610, and 11,395 women who survived married to age 50. Together, the three samples allow for comparisons over time and space. Using survival analyses, 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. However, we found little evidence that early fertility affects post-reproductive survival. We used Heckman’s procedure to assess the impact of mortality selection during reproductive years, with no appreciable alteration of the main results. We conclude by discussing the needs and the advantages of comparative approaches.