Table 2. The overall and stratified analysis for the association between MTHFR and T2DM.

Genetic Model	Subgroup	Model for meta-analysis	OR(95% CI)	P for heterogeneity	I2 (%)	P for Egger's test
Dominant	overall	R	1.70(1.42–2.02)	0.00	56.9	0.45
	Region
	Southern China	R	1.71(1.32,2.21)	0.04	49.6
	Northern China	R	1.68(1.32,2.14)	0.00	61.9
	HWE
	Yes	R	1.73(1.39,2.15)	0.00	60.5
	No	F	1.57(1.28,1.93)	0.07	47.8
Recessive	overall	R	1.48(1.21–1.80)	0.02	37.7	0.00
	Region
	Southern China	F	1.70(1.29–2.23)	0.81	0.00
	Northern China	R	1.39(1.07–1.81)	0.01	50.4
	HWE
	Yes	R	1.61(1.23–2.09)	0.01	44.3
	No	F	1.28(1.00–1.63)	0.34	11.6
Homozygous	overall	R	1.89(1.47–2.42)	0.00	50.0	0.01
	Region
	Southern China	F	2.07(1.56,2.76)	0.60	0.00
	Northern China	R	1.81(1.28,2.56)	0.00	62.1
	HWE
	Yes	R	2.13(1.53,2.95)	0.00	53.2
	No	F	1.51(1.16,1.96)	0.18	32.6
Heterozygous	overall	R	1.58(1.33–1.87)	0.00	46.4	0.33
	Region
	Southern China	R	1.57(1.18,2.08)	0.03	52.3
	Northern China	R	1.58(1.28,1.97)	0.02	46.0
	HWE
	Yes	R	1.59(1.30,1.95)	0.00	51.1
	No	F	1.52(1.20,1.92)	0.16	35.1
Additive	overall	R	1.46(1.28–1.68)	0.00	64.5	0.01
	Region
	Southern China	F	1.53(1.34,1.75)	0.29	16.6
	Northern China	R	1.42(1.17,1.72)	0.00	72.7
	HWE
	Yes	R	1.48(1.26,1.75)	0.00	66.9
	No	R	1.41(1.11,1.78)	0.02	64.5

OR: odds ratio; R: random-effects model; F: fix-effects model. HWE: Hardy-Weinbery equilibrium