TABLE III.

Univariate biometric genetic models for asthma and obesity

	Estimates of variance components†			Tests of model fit
Model*	Additive genetic (A)	Common environment (C)	Unique environment (E)	χ²	df	P Value	AIC‡
Asthma
ACE	0.35 (0.00–0.62)	0.17 (0.00–0.52)	0.49 (0.38–0.60)	-	-	-	-
AE	0.53 (0.41–0.63)	-	0.47 (0.37–0.59)	0.62	1	.43	−1.38
CE	-	0.46 (0.36–0.56)	0.54 (0.44–0.64)	2.37	1	.12	0.37
Obesity
ACE	0.77 (0.40–0.83)	0.00 (0.00–0.34)	0.23 (0.17–0.32)	-	-	-	-
AE	0.77 (0.68–0.83)	-	0.23 (0.17–0.32)	0.00	1	1.00	−2.00
CE	-	0.66 (0.58–0.73)	0.34 (0.27–0.42)	17.89	1	<.0001	15.89

^*ACE refers to a model that includes additive genetics (A), common environment (C), and unique environment (E); AE only includes additive genetics and unique environment; and CE only includes the common and unique environment.

^†Proportion of variance caused by additive genetics (a²), shared environment (c²), and unique environment (e²) according to each model.

^‡Akaike’s information criterion (AIC) is a global measure of goodness of fit; the best-fitting and most parsimonious models are shown in bold.