Table 3.

Heritability and biometric modelling in males with knee OA

Model in males	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	0.02 (0.01–0.02)	0.02 (0.01–0.02)	0.66 (0.03–0.92)	0.71 (0.39–0.87)	0.26 (0.05–0.70)	0.30 (0.13–0.55)	0 (0.00–0.89)	–	–	–	–	–3387.1	0.021	1	Compare CE, p = 0.65	6780.14
ACE	0.02 (0.01–0.02)	0.02 (0.01–0.02)	0.7 (0.42–0.85)	0.7 (0.42–0.85)	0.29 (0.14–0.51)	0.29 (0.14–0.51)	0	0	–	0.69 (0.48–0.90)	0.31 (0.1–0.52)	–3387.2	25.8	1	Compared AE, p <0.0001	6780.35
ADE	0.02 (0.01–0.02)	0.02 (0.01–0.02)	0.79 (0.45–0.93)	0.39 (0.28–0.50)	0.39 (0.18–0.66)	0.10 (0.07–0.16)	0.79 (0.57–1.0)	0.79 (0.57–1.0)	0	–	0.21 (0.0–0.43)	–3400.1	0	1	Compare DE, p = 1.0	6806.14
AE	0.02 (0.01–0.02)	0.02 (0.01–0.02)	0.79 (0.45–0.93)	0.39 (0.28–0.50)	0.39 (0.18–0.66)	0.10 (0.07–0.16)	0.79 (0.57–1.0)	0.79 (0.57–1.0)	–	–	0.21 (0.0–0.43)	–3400.1	25.8	1	Compare Sat, p <0.0001	6804.14
CE	0.02 (0.01–0.02)	0.02 (0.01–0.02)	0.69 (0.42–0.85)	0.69 (0.42–0.85)	0.29 (0.14–0.51)	0.29 (0.14–0.51)	–	–	_	0.69 (0.48–0.90)	0.31 (0.1–0.52)	–3387.2	0	1	Compare ACE, p  = 1.0	6778.35
DE	0.02 (0.01–0.02)	0.02 (0.01–0.02)	0.76 (0.38–0.92)	0.19 (0.13–0.25)	0.36 (0.14–0.66)	0.04 (0.03–0.06)	0.76 (0.51–1.0)	–	0.76 (0.51–1.0)	–	0.24 (0.00–0.49)	–3414.6	29.1	1	Compare ADE, P <0.0001	6833.24

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, OA osteoarthritis

The CE model in bold displayes the best model fit by the AIC. Fixing the additive genetic component at zero produced no worse fit (p=1.0)