Long-term trends and seasonality of omphalocele during 1996–2010 in China: a retrospective analysis based on the hospital-based birth defects surveillance system

Table 2 Comparison of the fitted results of the three models in each region/area of China

Model	k		Variables	Log likelihood	G²	p-value
National wide	0	Model A1	Region urban–rural age year	−2080.89
	1	Model A2	Region urban–rural age year c1 s1	−2078.47	4.85^a	0.088
	2	Model A3	Urban–rural age year c1 s1 c2 s2	−2077.84	1.26^b	0.533
South	0	Model B1	Urban–rural age year	−1075.90
	1	Model B2	Urban–rural age year c1 s1	−1075.26	1.27^c	0.530
	2	Model B3	Urban–rural age year c1 s1 c2 s2	−1074.86	0.81^d	0.667
North	0	Model C1	Urban–rural age year	−996.45
	1	Model C2	Urban–rural age year c1 s1	−994.30	4.31^e	0.116
	2	Model C3	Urban–rural age year c1 s1 c2 s2	−993.52	1.55^f	0.461
Urban	0	Model D1	Region age year	−1113.58
	1	Model D2	Region age year c1 s1	−1113.45	0.27^g	0.874
	2	Model D3	Region age year c1 s1 c2 s2	−1112.17	2.56^h	0.278
Rural	0	Model E1	Region age year	−964.87
	1	Model E2	Region age year c1 s1	−960.71	8.31ⁱ	0.016
	2	Model E3	Region age year c1 s1 c2 s2	−959.90	1.62^j	0.445

^aCompared model A2 with model A1; ^bCompared model A3 with model A2; ^cCompared model B2 with model B1; ^dCompared model B3 with model B2; ^eCompared model C2 with model C1; ^fCompared model C3 with model C2; ^gCompared model D2 with model D1; ^hCompared model D3 with model D2; ⁱCompared model E2 with model E1; ^jCompared model E3 with model E2.

ISSN: 1471-2393