Table 1. Main results for the MTHFR C677T mutation in the meta-analysis.

MTHFR C677T(rs18013133)	Na	TT vs CC			CT vs CC			CT/TT vs CC			TT vs CT/CC			T vs C
Variables		OR(95%CI)	Pb	FDRg	OR(95%CI)	Pb	FDRg	OR(95%CI)	Pb	FDRg	OR(95%CI)	Pb	FDRg	OR(95%CI)	Pb	FDRg
Total	32	1.62(1.29-2.04)	0.000	0.000	1.17(1.03-1.33)	0.000	0.016	1.26(1.10-1.45)	0.000	0.001	1.47(1.23-1.77)	0.002	0.000	1.25(1.12-1.40)	0.000	0.000
Consistent to HWE	29	1.70(1.35-2.14)	0.000	0.000	1.15(1.01-1.30)	0.001	0.068	1.26(1.09-1.45)	0.000	0.002	1.53(1.29-1.83)	0.015	0.000	1.27(1.14-1.42)	0.000	0.000
Ethnicity
European	9	1.23(0.81-1.85)	0.026	0.328	1.03(0.80-1.32)	0.046	0.978	1.08(0.84-1.40)	0.020	0.660	1.18(0.84-1.66)	0.085	0.411	1.10(0.91-1.34)	0.010	0.364
Asian	17	2.15(1.67-2.75)	0.036	0.000	1.28(1.13-1.46)	0.153	0.000	1.44(1.24-1.66)	0.019	0.000	1.79(1.48-2.16)	0.193	0.000	1.42(1.27-1.60)	0.005	0.000
American	2	2.17(1.06-4.42)	0.593	0.062	1.13(0.24-5.23)	0.004	0.978	1.27(0.33-4.78)	0.009	0.729	1.87(0.94-3.73)	0.830	0.125	1.42(0.67-3.00)	0.036	0.364
African	3	0.76(0.49-1.19)	0.582	0.296	0.78(0.61-1.01)	0.532	0.145	0.77(0.61-0.98)	0.555	0.090	0.84(0.54-1.29)	0.584	0.422	0.82(0.68-1.00)c	0.507	0.075
Sample Size
≧500	7	1.55(1.11-2.18)	0.023	0.010	1.19(0.97-1.46)	0.014	0.093	1.26(1.00-1.57)d	0.002	0.045	1.40(1.07-1.84)	0.095	0.015	1.23(1.03-1.47)	0.001	0.024
<500	25	1.66(1.22-2.25)	0.000	0.002	1.16(0.98-1.37)	0.001	0.093	1.26(1.05-1.51)	0.000	0.024	1.50(1.18-1.91)	0.004	0.002	1.26(1.09-1.46)	0.000	0.004
Subgroup
Azoospermia	14	1.64(1.12-2.42)	0.002	0.016	1.21(1.04-1.41)	0.298	0.016	1.31(1.06-1.61)	0.015	0.016	1.49(1.07-2.06)	0.011	0.017	1.27(1.05-1.54)	0.000	0.016
Consistent to HWE	11	1.83(1.25-2.67)	0.018	0.004	1.21(1.03-1.42)	0.209	0.044	1.33(1.05-1.67)	0.018	0.032	1.63(1.21-2.20)	0.092	0.002	1.32(1.09-1.59)	0.002	0.008
European	3	0.99(0.35-2.82)	0.139	0.992	1.09(0.77-1.53)	0.647	0.635	1.07(0.76-1.51)	0.344	0.829	0.94(0.36-2.44)	0.166	0.905	1.08(0.73-1.59)	0.122	0.716
Asian	6	2.56(1.93-3.40)	0.820	0.000	1.46(1.19-1.80)	0.824	0.000	1.69(1.39-2.06)	0.825	0.000	2.04(1.59-2.61)	0.689	0.000	1.59(1.39-1.82)	0.807	0.000
African	3	0.81(0.47-1.38)	0.558	0.540	0.79(0.57-1.09)	0.700	0.248	0.79(0.58-1.06)	0.754	0.198	0.89(0.53-1.49)	0.492	0.811	0.84(0.66-1.07)	0.625	0.252
≧300	8	1.99(1.34-2.95)	0.032	0.002	1.24(1.04-1.48)	0.119	0.028	1.40(1.07-1.83)	0.013	0.028	1.72(1.27-2.35)	0.116	0.002	1.37(1.11-1.69)	0.003	0.008
OATf	16	1.52(1.12-2.06)	0.008	0.018	1.17(0.96-1.44)	0.001	0.127	1.25(1.01-1.55)	0.000	0.053	1.43(1.13-1.82)	0.098	0.015	1.24(1.05-1.47)	0.000	0.058
Consistent to HWE	14	1.56(1.15-2.11)	0.017	0.008	1.11(0.92-1.34)	0.016	0.542	1.21(0.99-1.48)	0.001	0.118	1.47(1.17-1.86)	0.153	0.002	1.24(1.06-1.45)	0.000	0.016
European	3	1.49(0.63-3.50)	0.141	0.369	0.98(0.69-1.38)	0.345	0.906	1.13(0.73-1.75)	0.163	0.592	1.47(0.71-3.04)	0.196	0.503	1.44(0.82-1.86)	0.071	0.304
Asian	9	1.78(1.25-2.52)	0.034	0.005	1.20(0.96-1.51)	0.023	0.275	1.32(1.05-1.67)	0.006	0.048	1.61(1.24-2.08)	0.196	0.000	1.32(1.11-1.58)	0.005	0.005
African	2	0.74(0.38-1.43)	0.666	0.369	0.78(0.54-1.14)	0.305	0.337	0.77(0.55-1.08)	0.315	0.158	0.81(0.42-1.53)	0.875	0.511	0.82(0.63-1.07)	0.384	0.171
≧300	9	1.39(1.00-1.93)e	0.051	0.084	1.16(0.88-1.51)	0.000	0.287	1.20(0.93-1.57)	0.000	0.168	1.33(1.03-1.71)	0.240	0.055	1.20(0.98-1.46)	0.000	0.113

^aNumber of studies.

^bThe value of heterogeneity test.

^cThe exact value is 0.823(0.681-0.996).

^dThe exact value is 1.257(1.005-1.571).

^eThe exact value is 1.390(1.001-1.929).

^fIncluding OAT, severe OAT, oligozoospermia, and teratozoospermia.

^gp value in multiple testing (Benjamini-Hochberg methods).