Table 5.

Biometric models and chi-square test statistics, sex adjusted

Model	MZ prevalence	DZ prevalence	MZ rho	DZ rho	MZ cwc	DZ cwc	H	Variance component estimates				Chi-square test statistics
								A	D	C	E	LL	–2ln	df	p value	AIC
Sat	0.03 (0.03–0.04)	0.03 (0.03–0.04)	0.79 (0.59–0.90)	0.70 (0.50–0.83)	0.44 (0.28–0.62)	0.35 (0.22–0.51)	0.18 (0.00–0.62)	–	–	–	–	–10014.6	3.87	1	Compare CE, p = 0.05	20,037.10
ACE	0.03 (0.03–0.04)	0.03 (0.03–0.04)	0.79 (0.59–0.90)	0.70 (0.50–0.83)	0.44 (0.28–0.62)	0.35 (0.22–0.51)	0.18 (0.0–0.62)	0.18 (0.0–0.62)	–	0.61 (0.25–0.97)	0.21 (0.06–0.36)	–10014.5	44.6	1	Compare AE, p <0.0001	20,037.10
ADE	0.03 (0.03–0.04)	0.03 (0.03–0.04)	0.83 (0.68–0.91)	0.41 (0.36–0.47)	0.49 (0.35–0.64)	0.16 (0.13–0.19)	0.83 (0.72–0.94)	0.83 (0.72–0.94)	0	–	0.17 (0.06–0.28)	–10036.8	0	1	Compare AE, p = 1.0	20,081.66
AE	0.03 (0.03–0.04)	0.03 (0.03–0.04)	0.83 (0.68–0.91)	0.41 (0.36–0.47)	0.49 (0.35–0.64)	0.16 (0.13–0.19)	0.83 (0.72–0.94)	0.83 (0.72–0.94)	–	–	0.17 (0.06–0.28)	–10036.8	34.3	1	Compared ACE, p <0.0001	20,079.66
CE	0.03 (0.03–0.04)	0.03 (0.03–0.04)	0.74 (0.61–0.83)	0.74 (0.61–0.83)	0.39 (0.29–0.51)	0.39 (0.29–0.51)	–	–	–	0.74 (0.63–0.85)	0.26 (0.15–0.37)	–10016.5	3.87	1	Compare ACE, p = 0.05	20,038.97
DE	0.03 (0.03–0.04)	0.03 (0.03–0.04)	0.82 (0.66–0.91)	0.20 (0.17–0.23)	0.48 (0.33–0.63)	0.08 (0.07–0.09)	0.81 (0.70–0.94)	–	0.82 (0.70–0.94)	–	0.18 (0.06–0.30)	–10067.7	61.7	1	Compare ADE, p <0.0001	20,141.35

A additive genetic, AIC Akaike’s Information Criterion, C common environment, cwc case-wise concordance rate, D dominant genetic, df degrees of freedom, DZ dizygotic, E unique environment, H broad sense heritability, LL = log likelihood of model, –2ln = Likelihood Ratio chi-square test, MZ monozygotic, rho tetrachoric correlation coefficient, Sat saturated model.

The ACE model in bold displayes the best model fit by the AIC. Fixing the common environmental component C at zero produced a significantly worse fit (p <0.0001).