Table 2. Results of meta-analysis for KCNJ11 E23K polymorphism and T2D risk.

Sub-group analysis	No. of studies	K allele				Heterozygous				Homozygous
		OR (95%CI)	P(Z)	P(Q)a	P(Q)b	OR (95%CI)	P(Z)	P(Q)a	P(Q)b	OR (95%CI)	P(Z)	P(Q)a	P(Q)b
Ethnicity					0.10				0.06				0.01
Caucasians	22	1.12 (1.08–1.16)	<10−5	0.001		1.09 (1.06–1.13)	<10−5	0.13		1.33 (1.18–1.50)	<10−5	0.0008
East Asians	14	1.13 (1.08–1.17)	<10−5	0.02		1.13 (1.05–1.22)	0.0009	0.02		1.30 (1.18–1.42)	<10−5	0.06
Indians	5	1.06 (0.87–1.29)	0.56	<10−5		1.00 (0.82–1.23)	0.98	0.01		0.90 (0.69–1.18)	0.45	0.02
Others	7	1.09 (0.97–1.23)	0.15	0.01		0.98 (0.76–1.28)	0.91	<10−4		1.19 (1.00–1.43)	0.05	0.31
Sample size					0.32				0.14				0.04
Large	22	1.12 (1.08–1.17)	<10−5	<10−5		1.12 (1.10–1.15)	<10−4	0.12		1.17 (1.07–1.28)	0.007	0.02
Small	26	1.13 (1.07–1.18)	<10−5	<10−5		1.10 (1.02–1.19)	0.009	0.002		1.32 (1.20–1.46)	<10−5	0.0007
Mean BMI of cases					0.37				0.20				0.03
<25	12	1.15 (1.11–1.21)	<10−5	0.15		1.15 (1.08–1.22)	<10−5	0.21		1.40 (1.28–1.55)	<10−5	0.74
25∼30	25	1.12 (1.06–1.19)	<10−4	<10−4		1.13 (1.06–1.21)	<10−4	0.004		1.18 (1.03–1.34)	0.008	<10−4
>30	6	1.10 (1.03–1.18)	0.008	0.07		1.11 (1.04–1.19)	0.001	0.09		1.16 (1.01–1.33)	0.02	0.10
Total	48	1.12 (1.09–1.16)	<10−5	<10−5		1.09 (1.03–1.14)	<10−5	0.0001		1.26 (1.17–1.35)	<10−5	<10−5

P(Z): Z test used to determine the significance of the overall OR.

P(Q)^a: Cochran's chi-square Q statistic test used to assess the heterogeneity in subgroups.

P(Q)^b: Cochran's chi-square Q statistic test used to assess the heterogeneity between subgroups.