Table 2.

Biometric twin model results: Alzheimer’s disease PRS at P < 1 × 10⁻⁵

Model	VC	Full model				Reduced model
		Est	SE	LL	UL	Est	SE	LL	UL
0. ACE	A	0.960	0.294	0.391	1.546	0.707	0.074	0.542	0.832
	C	−0.232	0.265	−0.774	0.258	—	—	—	—
	E	0.272	0.073	0.153	0.440	0.293	0.074	0.168	0.458
	−2LL	888.71				889.52
	AIC	902.71				901.52
	BIC	931.46				926.16
1. PRS	A P	0.136	0.040	0.058	0.342	0.101	0.029	0.051	0.164
	A B	0.882	0.083	0.343	1.410	0.614	0.075	0.452	0.744
	C	0.003	4.26E−4	−9.31E−7	0.668	—	—	—	—
	E	0.263	0.069	0.149	0.425	0.285	0.072	0.164	0.446
	covAC	−0.142	0.008	−0.618	0.098	—	—	—	—
	−2LL	2746.32				2747.52
	AIC	2768.32				2765.52
	BIC	2813.49				2802.48
2. PRS.no.APOE	A P	0.030	0.020	0.012	0.139	0.024	0.016	0.004	0.065
	A B	0.924	0.080	0.367	1.498	0.685	0.075	0.519	0.811
	C	4.29E−4	3.07E−4	−1.75E−6	1.101	—	—	—	—
	E	0.271	0.071	0.152	0.439	0.291	0.074	0.167	0.456
	covAC	−0.113	0.005	−0.781	0.115	—	—	—	—
	−2LL	2824.69				2825.45
	AIC	2846.69				2843.45
	BIC	2891.87				2880.42
3. PRS.no.APOE + ɛ4 alleles	A P	0.027	0.013	0.025	0.087	0.021	0.015	0.005	0.059
	A e4	0.118	0.024	0.049	0.242	0.093	0.027	0.046	0.152
	A B	0.825	0.077	0.318	1.351	0.596	0.075	0.434	0.728
	C	4.17E−4	4.94E−4	−5.419E−11	0.474	—	—	—	—
	E	0.268	0.069	0.153	0.433	0.289	0.073	0.167	0.451
	covAC	−0.120	0.007	−0.491	0.115	—	—	—	—
	−2LL	3783.69				3784.47
	AIC	3811.69				3808.47
	BIC	3869.19				3857.76

Biometrical analyses of Alzheimer’s disease risk with entry of a PRS were fitted adapting code in Dolan et al.³⁴ using OpenMx.³³ VC, variance component; Est, Estimate; SE, standard error; LL, lower 95% confidence interval; UL, upper 95% confidence interval; PRS, polygenic risk score at P < 1 × 10⁻⁵ residualized for four PCs and standardized within array type; PRS.no.APOE, PRS without APOE region; A, additive genetic influences; C, common environmental influences; E, non-shared environmental influences; A_P, genetic influences due to the PRS; A_ɛ4, genetic influences due to APOE ɛ4 alleles; A_B, background additive genetic influences; total A = A_P + A_B + 2covAC. The Reduced Model dropped C (common environmental variance) and covAC. All models adjusted for Sex, LastAge and LastAge². 95% confidence intervals are shown.