Extended maternal age at birth of last child and women's longevity in the Long Life Family Study

Abstract

Objective: This study investigated the association between maternal age at birth of last child and likelihood of survival to advanced age.

Methods: This was a nested case-control study using Long Life Family Study data. Three hundred eleven women who survived past the oldest 5th percentile of survival (according to birth cohort-matched life tables) were identified as cases, and 151 women who died at ages younger than the top 5th percentile of survival were identified as controls. A Bayesian mixed-effect logistic regression model was used to estimate the association between maternal age at birth of last child and exceptional longevity among these 462 women.

Results: We found a significant association for older maternal age, whereby women who had their last child beyond age 33 years had twice the odds for survival to the top 5th percentile of survival for their birth cohorts compared with women who had their last child by age 29 years (age between 33 and 37 y: odds ratio, 2.08; 95% CI, 1.13 to 3.92; older age: odds ratio, 1.92; 95% CI, 1.03 to 3.68).

Conclusions: This study supports findings from other studies demonstrating a positive association between older maternal age and greater odds for surviving to an unusually old age.

Figure 1

The increasing trend of the two lines shows the positive association of maternal age at last child and exceptional longevity. The downwards shift of the lines for increasing parity shows the negative effect of parity on the odds for exceptional longevity. For example, while a difference in maternal age at last child of about 14 years increases the odds for exceptional longevity by 2 in women with 1 or 2 children, the same effect in women with 3+ children would require a difference of 24 years in age at last child.