Table 2. Subgroup analysis of genetic variants in GDM (with HWE excluded only).

Subgroup	Number of studies	Number of cases	Number of controls	OR(95% CI)	P (Z)a	Heterogeneity
						I2	P (Q)b
MTNR1B rs10830963
Ethnicity
Asian	4	2090	2600	1.23 (1.10, 1.38)	<0.001	37.7%	0.186
Caucasian	1	458	422	1.49 (1.22, 1.82)	<0.001	NA	NA
OGTT
75 g	3	895	993	1.38 (1.20, 1.57)	<0.001	0.0%	0.375
100 g	2	1653	2029	1.20 (1.01, 1.44)	0.043	72.6%	0.056
Genotype method
Taqman assay	3	2111	2451	1.28 (1.08, 1.51)	0.004	72.2%	0.027
Others	2	437	571	1.29 (1.08, 1.54)	0.005	0.0%	0.375
Sample size
small	1	87	91	1.53 (1.01, 2.32)	0.047	NA	NA
large	4	2461	2931	1.27 (1.12, 1.44)	<0.001	58.4%	0.066
Pre-BMI
<25	2	812	1130	1.22 (0.9, 1.65)	0.202	54.2%	0.14
≥25	1	350	480	1.24 (1.02, 1.51)	0.033	NA	NA
TCF7L2 rs7903146
Ethnicity
Asian	3	1008	801	1.58 (1.12, 2.23)	0.009	39.1%	0.194
Caucasian	4	1119	2070	1.32 (0.86, 2.03)	0.212	91.4%	0.212
OGTT
75 g	5	1219	2170	1.43 (0.97, 2.09)	0.07	89.7%	<0.001
100 g	2	908	701	1.36 (0.94, 1.97)	0.100	12.3%	0.286
Genotype method
Taqman assay	4	1839	2590	1.24 (0.82, 1.87)	0.306	90.1%	<0.001
Others	3	288	281	1.73 (1.20, 2.50)	0.003	49.8%	0.136
IRS1 rs1801278
Ethnicity
Asian	2	262	400	2.15 (0.80, 5.74)	0.128	50.3%	0.156
Caucasian	3	1045	1573	1.41 (0.99, 2.01)	0.059	56.3%	0.101
OGTT
75 g	2	736	1296	1.31 (0.82, 2.08)	0.261	70.3%	0.067
100 g	3	571	677	1.88 (1.21, 2.94)	0.005	6.8%	0.342
Genotype method
Taqman assay	1	588	1189	1.04 (0.75, 1.45)	0.805	NA	NA
Others	4	719	784	1.77 (1.33, 2.35)	<0.001	0.0%	0.515
PPARG rs1801282
Ethnicity
Asian	5	1259	1126	0.72 (0.56, 0.93)	0.011	24.8%	0.256
Caucasian	3	1285	1889	1.07 (0.91, 1.18)	0.611	0.0%	0.474
OGTT
75 g	5	1519	2242	0.98 (0.86, 1.12)	0.812	51.7%	0.082
100 g	3	1025	773	0.80 (0.53, 1.21)	0.294	24.3%	0.267
Genotype method
Taqman assay	2	1505	1864	0.95 (0.71, 1.26)	0.706	55.9%	0.132
Others	6	1039	1151	0.87 (0.71, 1.05)	0.141	45.3%	0.104

^aP values in subgroups.

^bP values for Cochran’s Q statistic test used to assess the heterogeneity.

NA not available.