Table 4.

Bivariate structural equation models of depression and obesity in female twin pairs

	Estimates of variance components (95% Confidence Intervals)			Test of model fit
Shared component	Additive genetic (A)	Common environment (C)	Unique environment (E)	χ 2	df	P value	AIC*
ACE				–	–	–	–
Depression	0.38 (0.03, 0.64)	0.16 (0.05, 0.48)	0.45 (0.35, 0.56)
Obesity	0.59 (0.20, 0.84)	0.21 (0.00, 0.56)	0.20 (0.13, 0.29)
CE				0.75	1	0.39	−1.25
Depression	0.36 (0.00, 0.61)	0.18 (0.08, 0.54)	0.46 (0.36, 0.57)
Obesity	0.57 (0.19, 0.84)	0.23 (0.00, 0.58)	0.20 (0.14, 0.30)
AE				0.01	1	0.92	−1.99
Depression	0.38 (0.01, 0.64)	0.17 (0.00, 0.52)	0.45 (0.35, 0.56)
Obesity	0.58 (0.20, 0.69)	0.22 (0.00, 0.56)	0.20 (0.13, 0.29)
AC				1.16	1	0.28	−0.84
Depression	0.38 (0.01, 0.64)	0.16 (0.00, 0.51)	0.45 (0.35 (0.56)
Obesity	0.57 (0.20, 0.86)	0.21 (0.00, 0.56)	0.20 (0.13, 0.29)
A				1.32	2	0.52	−2.68
Depression	0.38 (0.02, 0.64)	0.17 (0.00, 0.51)	0.45 (0.36, 0.56)
Obesity	0.58 (0.20, 0.87)	0.22 (0.00, 0.57)	0.20 (0.13, 0.29)
C				3.24	2	0.20	−0.76
Depression	0.37 (0.00, 0.60)	0.17 (0.07, 0.53)	0.45 (0.36, 0.57)
Obesity	0.58 (0.20, 0.82)	0.22 (0.02, 0.57)	0.20 (0.16, 0.30)
E				5.73	2	0.06	1.27
Depression	0.36 (0.00, 0.63)	0.17 (0.00, 0.53)	0.46 (0.36, 0.58)
Obesity	0.56 (0.18, 0.85)	0.22 (0.00, 0.42)	0.21 (0.15, 0.31)
None				12.89	3	0.01	6.89
Depression	0.38 (0.00, 0.64)	0.16 (0.00, 0.53)	0.45 (0.36, 0.57)
Obesity	0.59 (0.20, 0.86)	0.21 (0.00, 0.56)	0.20 (0.13, 0.30)

^*Akaike‘s information criterion (AIC) is a global measure of goodness of fit; the best-fitting and most parsimonious model is shown in bold.