Genetic and environmental influence on lung function impairment in Swedish twins

Respiratory Research

Table 5 Fit statistics from structural equation modelling for FEV₁.

	-2LL	df	AIC	Diff Chi-2	Diff df	p
Unadjusted
Model 1	2908,199	343	2222,199
Model 2 vs. 1	2908,199	344	2220,199	0,000	1	0,986
Model 3 vs. 2	2916,168	347	2222,168	7,969	3	0,047
Adj. PY
Model 1	2864,305	341	2182,305
Model 2 vs. 1	2864,305	342	2180,305	0,001	1	0,980
Model 3 vs. 2	2171,283	345	2181,283	6,978	3	0,073
Adj. PY, sympt.
Model 1	2845,428	339	2167,428
Model 2 vs. 1	2845,448	340	2165,448	0,021	1	0,885
Model 3 vs. 2	2853,815	343	2167,815	8,367	3	0,039

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