Postreproductive Longevity in a Natural Fertility Population

Abstract

Fertility patterns may be useful markers for rates of biological aging. From historical data for the population of Quebec (taken in the “Registre de population du Québec ancien”, at the University of Montreal), we examine the effects of reproduction on longevity from evolutionary and sociodemographic perspectives. Using Cox hazard models on 1,923 women and 1,926 men married in the colony before 1740, we show that women bearing their last child late in life had longer postreproductive lives, suggesting that late menopause is associated with an overall slower rate of aging. Increased parity had an opposite, detrimental effect on women’s postreproductive survival. On the other hand, husbands’ longevity was less sensitive to parity and reproductive history. For husbands, increased effective family size (EFS), i.e., the number of children who survived up to age 18 in a “compressed” reproductive time span meant higher chances for survival past age 60. Children may serve as valuable economic assets on farmsteads during colonization, which would mostly benefit fathers. In a collaborative effort to unveil postreproductive aging patterns in historical populations, the results are compared to previous analyses conducted on the Utah Population Database and evolutionary and sociodemographic theories are addressed in light of these results.