Parental age at birth and longevity of offspring in centenarian families: the role of biology, social interaction and culture

Valérie Jarry, Université de Montréal
Alain Gagnon, Université de Montréal
Robert R. Bourbeau, Université de Montréal

Previous studies showed that siblings of centenarians experienced a survival advantage compared to their birth cohort, revealing that surviving to very old ages is modulated by a familial component, whether genetic or environmental. However, mortality differences remain between siblings, reflecting differences in individual non-shared characteristics. In this study we determined the extent to which parental age at child’s birth and seasonality have an impact on longevity of the child and on survival to age 100. We used an event-history database that links ages at death of 800 validated centenarians and their siblings to their childhood characteristics gathered from the 1901 and 1911 Canadian census records. The following variables were explored and included in the models: sex, birth order, family size, paternal age at the child's birth, maternal age at the child's birth, and the season of birth. We used fixed-effects models to capture the underlying family level heterogeneity that could affect the survival of children. Our results show that, while paternal age at child’s birth does not seem to play, children born to mothers between 25 and 29 years of age had more than twice the chances to survive to age 100 compared to their brothers and sisters born to 40-year-old-and-older mothers.