Achieving exceptional survival: are socioeconomic conditions in childhood still important?

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

Previous studies showed that siblings of centenarians experienced greater longevity than their birth cohort, revealing that surviving to very old ages is modulated by a familial component. Furthermore, a substantial body of literature has focused on early familial life as a source of longevity differential in very old age. However, less established in the literature is whether childhood conditions have the same effect within long lived families. In this paper we discuss early-life factors which could affect an individual’s chance to reach the advanced ages, with particular focus on siblings of centenarians. We utilized an event-history database that links age at death of individuals to their childhood characteristics gathered from the 1901 and 1911 Canadian census records. We verify on one hand if early-life factors that influence a normal person's survival also have an effect on the longevity of long-lived persons. On the other hand, we compare the influence of childhood conditions on the odds of surviving, first from age 40 to age 75 and then, from age 75 to age 90. The effects of early-life conditions were found to be much smaller for women than for men as well as for siblings of centenarians, suggesting that siblings of centenarians have a possible favorable genetic background or biological robustness. Moreover, we found that influence of early-life socioeconomic factors lessen in older age, drawing a distinction between determinants involved in normal lifespan and those that lead to exceptionally old age.