Table 3.

Associations between polygenic scores for age‐at‐first‐birth and disinhibitory behaviors in two birth cohorts

Outcome	Effect size	E‐Risk cohort (N = 1,999)							Dunedin cohort (N = 918)
		Age assessed (years)	N	Mean [SD] or n (%)	Association	p‐Value a	Cohen's d b	Pearson's r b	Age assessed (years)	N	Mean [SD] or n (%)	Association	p‐Value a	Cohen's d	Pearson's r
Primary outcomes c
Low childhood self‐control d	β	5–10	1,999	0.01 [0.99]	.07 [.02–.12]	.006	.15	.08	3–11	918	−0.02 [0.95]	.12 [.06–.18]	<.001	.25	.13
Externalizing liability e	β	18	1,863	0.01 [1.00]	.08 [.03–.13]	.004	.17	.08	18–38	918	−0.03 [0.98]	.08 [.02–.14]	.015	.16	.08
Criminal offending	RR	10–22	1,857	n = 208 (11.2%)	1.16 [1.01–1.33]	.039	.12	.06	14–38	898	n = 238 (26.5%)	1.18 [1.04–1.34]	.010	.17	.09
Substance dependence	RR	18	1,860	n = 413 (22.2%)	1.14 [1.04–1.24]	.006	.16	.08	38	886	n = 165 (18.6%)	1.19 [1.02–1.38]	.028	.15	.07
Informant‐reported disinhibition f	β	18	1,851	0.01 [1.01]	.07 [.02–.12]	.007	.16	.08	38	873	−0.02 [0.98]	.02 [−.04–.09]	.501	.05	.02
Secondary outcome c
Lifetime number of sexual partners	IRR	18	1,810	1.90 [2.00]	1.12 [1.06–1.18]	<.001	.25	.12	38	914	17.39 [15.18]	1.07 [1.01–1.14]	.016	.16	.08

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. Brackets indicate 95% confidence intervals. β, standardized regression coefficient; IRR, incidence rate ratio; RR, risk ratio.

^aOur analysis prioritizes the reporting of effect sizes and their uncertainty; however, we also report p‐values for full disclosure. Within each cohort, the Bonferroni‐adjusted p‐value for tests of associations with primary outcomes is .010.

^bAverage effect size across three approaches used to account for the clustering of twins within families. All approaches produced very similar estimates, available on request from the corresponding author.

^cPrimary outcomes were prespecified. Secondary outcome was added in response to peer review.

^dThe self‐control factor was standardized (M = 0, SD = 1) within the full samples (E‐Risk: N = 2,232, Dunedin: N = 1,037). Higher scores indicate lower levels of self‐control.

^eThe externalizing liability factor was standardized (M = 0, SD = 1) within the full sample of E‐Risk participants at age 18 (N = 2,066) and the full sample of Dunedin participants with externalizing data for at least one assessment between ages 18 and 38 (N = 1,000).

^fInformant‐reported disinhibition was standardized (M = 0, SD = 1) within the full samples of participants with informant‐report data (E‐Risk: N = 2,052, Dunedin: N = 934).