Table 2

Parameter estimates of the risk score models for the prediction of GDM in the training dataset

Variables used in the predicting model	Univariate analysis		Multivariate analysis Model 1				Multivariate analysis Model 2
Variables used in the predicting model	OR (95% CI)	P value	β	SE	OR (95% CI)	P value	β	SE	OR (95% CI)	P value
Variables at first antenatal care visit
Maternal age, year	1.10 (1.07 to 1.13)	<0.001	0.0941	0.0115	1.10 (1.07 to 1.12)	<0.001	0.0978	0.0142	1.10 (1.07 to 1.13)	<0.001
BMI at registration, kg/m²	1.12 (1.07 to 1.16)	<0.001	0.1278	0.0099	1.14 (1.11 to 1.16)	<0.001	0.1366	0.0123	1.15 (1.12 to 1.17)	<0.001
Height, cm	0.98 (0.96 to 0.99)	0.038	−0.0270	0.0078	0.97 (0.96 to 0.99)	0.001	−0.0215	0.0096	0.98 (0.96 to 1.00)	0.024
Systolic blood pressure, mm Hg	1.01 (1.00 to 1.02)	0.006	0.0093	0.0035	1.01 (1.00 to 1.02)	0.008	0.0130	0.0043	1.01 (1.00 to 1.02)	0.002
ALT,U/L*	1.73 (1.10 to 2.71)	0.024	0.6816	0.1624	1.98 (1.44 to 2.72)	<0.001	0.7004	0.1973	2.01 (1.37 to 2.97)	<0.001
Family history of diabetes	1.62 (1.25 to 2.09)	<0.001	0.5129	0.1048	1.67 (1.36 to 2.05)	<0.001	0.4909	0.1270	1.63 (1.27 to 2.10)	<0.001
Waist circumference, cm	1.01 (0.99 to 1.02)	0.022			Not selected				Not selected
Non-AB blood type	1.31 (0.97 to 1.79)	0.082			Not selected				Not selected
Active smoking prepregnancy	1.16 (0.80 to 1.68)	0.442			Not selected				Not selected
BMI*ALT†	1.30 (0.95 to 1.79)	0.078			Not selected				Not selected
BMI*Height†	1.20 (0.75 to 1.92)	0.405			Not selected				Not selected
Variables at GCT
Physical activity during pregnancy	0.80 (0.64 to 1.00)	0.038			Not selected		−0.2374	0.1141	0.79 (0.63 to 0.99)	0.038
Sitting time at home during pregnancy	1.15 (0.99 to 1.33)	0.050			Not selected		0.1825	0.0728	1.20 (1.04 to 1.38)	0.012
Weight gain from registration to GCT, kg	0.99 (0.97 to 1.01)	0.388			Not selected		0.0351	0.0130	1.04 (1.01 to 1.06)	0.007
Passive smoking during pregnancy	1.41 (1.15 to 1.74)	0.001			Not selected		0.3058	0.1001	1.36 (1.12 to 1.65)	0.002
Sleeping quality during pregnancy	1.21 (1.01 to 1.44)	0.029			Not selected				Not selected
Sleeping time during pregnancy	1.06 (0.97 to 1.17)	0.225			Not selected				Not selected
BMI*PSMK†	0.74 (0.50 to 1.09)	0.119			Not selected				Not selected
Constant			−5.7469	1.3508			−8.0732	1.6667

*ALT was log-transformed;
†The additive interaction of two variables.
ALT, alanine aminotransferase; BMI, body mass index; GCT, 50 g 1-hour glucose challenge test; GDM, gestational diabetes mellitus; PSMK, passive smoking during pregnancy.