Maternal age, birth order and other early-life factors: a family-level approach to exploring exceptional survival
Bibliographic record
Abstract
The literature provides increasing empirical support for the idea that early-life experiences can greatly shape someone’s future health and longevity. Besides shared early-life conditions, within-family variation in maternal age at time of childbirth and birth order have been found to be related to later-life survival. In this study, we examine whether there is a persisting effect of maternal age and birth order on survival to age 104 when both variables are considered and adjusted for season of birth and birth spacing. To address potential confounding by unmeasured family-level factors, we apply a case-sibling control analysis. Using data on 273 centenarians born in Quebec in the 1890–1900 period and their siblings, we show that children born to mothers over age 40 are less likely to reach age 104 while third- and fourthborn children are more likely to make this landmark. When examining the effect of maternal age in combination with the effect of birth order, we obtain higher estimates of both maternal age effects and birth order effects, indicating that the measured influence of one is suppressed when the other is not accounted for. We argue that being born early in the sibling row may provide a biological advantage related in part to the quality of the female reproductive system, but this effect may be counterbalanced by the precariousness of the family as a socio-economic unit at the earliest stages of its cycle. No mediation of these effects is seen when including birth spacing and season of birth. However, we find that birth order differences in longevity are most prominent among siblings born to older mothers and in families where the father was a farmer. We discuss other possible social and historical pathways through which maternal age, birth order and season of birth may operate to mould the offspring’s longevity.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".