Table 1.
Risk ratios for associations between a polygenic score for age‐at‐first‐birth and reproductive behaviors
| Outcome a | Pooled E‐Risk and Dunedin cohorts (N = 2,917) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Analytic N | Cases (%) | Baseline | p‐Value b | Cohen's d c | Pearson's r c | Adjusted for SES | p‐Value | Adjusted for maternal AFB | p‐Value | Adjusted for SES and maternal AFB | p‐Value | |
| Intercourse | 2,736 | 1,982 (72.4) | 1.06 [1.04–1.09] | <.001 | .21 | .10 | 1.05 [1.03–1.08] | <.001 | 1.05 [1.02–1.07] | <.001 | 1.04 [1.02–1.07] | <.001 |
| Pregnancy | 2,734 | 248 (9.1) | 1.25 [1.12‐1.41] | <.001 | .17 | .08 | 1.17 [1.04–1.32] | .008 | 1.14 [1.02–1.28] | .024 | 1.12 [1.00–1.26] | .057 |
| Birth | 2,737 | 76 (2.8) | 1.25 [0.99–1.59] | .065 | .08 | .04 | 1.12 [0.88–1.42] | .355 | 1.10 [0.88–1.39] | .402 | 1.05 [0.83–1.33] | .684 |
The polygenic score was reverse‐coded. Analyses were restricted to the Caucasian samples (E‐Risk: N = 1,999, Dunedin: N = 918). Models controlled for sex and cohort/study. Brackets indicate 95% confidence intervals. AFB, age‐at‐first‐birth; SES, childhood socioeconomic status.
Binary variables, coded to reflect whether participants had met each reproductive milestone by age 18 or younger.
Our analysis prioritizes the reporting of effect sizes and their uncertainty; however, we also report p‐values for full disclosure. The Bonferroni‐adjusted p‐value for tests of baseline associations is .017.
Average effect size across three approaches used to account for the clustering of E‐Risk twins within families. All approaches produced very similar estimates, available on request from the corresponding author.