Genetic and environmental influence on lung function impairment in Swedish twins

Respiratory Research

Table 4 Fit statistics from structural equation modelling for VC.

	-2LL	df	AIC	Diff Chi-2	Diff df	p
Unadjusted
Model 1	2827,767	343	2141,767
Model 2 vs. 1	2827,870	344	2139,870	0,103	1	0,748
Model 3 vs.2	2829,011	347	2135,011	1,141	3	0,767
Adj. PY
Model 1	2812,858	341	2130,858
Model 2 vs.1	2812,859	342	2128,859	0,001	1	0,976
Model 3 vs.2	2815,019	345	2125,019	2,161	3	0,540
Adj. PY, sympt.
Model 1	2805,169	339	2127,169
Model 2 vs.1	2805,215	340	2125,215	0,046	1	0,830
Model 3 vs.2	2809,601	343	2123,601	4,386	3	0,223

Models: 1) rg (genetic correlation) free for DZ opposite-sex twins, ACE different for men and women. 3) rg fixed at 0.5 for DZ OS, ACE different for men and women. 4) rg fixed at 0.5 for DZ OS, ACE same for men and women, df = degrees of freedom, PY= pack years

ISSN: 1465-993X