Table 4.

Pooled ORs and 95% CIs of the association between maternal MTHFR C677T polymorphism and CHD.

Contrasts	No. of studies	Total case/control	T vs. C			TT vs. CC			TT + CT vs. CC			TT vs. TC + CC
			OR	95% CI	PH	OR	95% CI	PH	OR	95% CI	PH	OR	95% CI	PH
All	14	1745/2044	1.103	0.999–1.218	0.018	1.254	1.012–1.553	0.167	1.105	0.958–1.275	0.220	1.235	1.024–1.489	0.098
Study in HWE	12	1523/1515	1.098	0.984–1.224	0.007	1.247	0.986–1.578	0.104	1.092	0.935–1.275	0.130	1.244	1.012–1.528	0.076
Ethnicity
Caucasian	10	1311/1531	1.062	0.945–1.193	0.014	1.189	0.925–1.527	0.121	1.067	0.909–1.251	0.145	1.165	0.926–1.466	0.066
Asian	4	434/513	1.204	0.973–1.490	0.175	1.454	0.921–2.295	0.207	1.170	0.802–1.707	0.438	1.431	1.011–2.024	0.228
Types of CHD
All types	11	1586/1742	1.072	0.960–1.197	0.016	1.202	0.947–1.525	0.140	1.071	0.917–1.250	0.197	1.192	0.964–1.474	0.067
CD	1	103/200	1.043	0.745–1.461	–	1.107	0.554–2.213	–	0.989	0.576–1.699	–	1.150	0.645–2.052	–
ASD/PDA	1	56/102	1.697	1.054–2.731	–	3.067	1.048–8.974	–	2.033	0.765–5.403	–	2.147	1.068–4.314	–
Source of controls
HB	6	514/750	1.092	0.883–1.351	0.004	1.504	0.999–2.264	0.120	0.952	0.701–1.293	0.156	1.550	1.106–2.170	0.099
PB	6	1175/1192	1.060	0.936–1.201	0.573	1.078	0.823–1.412	0.500	1.090	0.914–1.300	0.135	1.028	0.803–1.318	0.500
Sample size
Small	6	1441/1486	1.081	0.963–1.214	0.884	1.110	0.865–1.425	0.672	1.115	0.947–1.314	0.977	1.090	0.874–1.361	0.333
Large	7	304/558	1.136	0.913–1.412	0.001	1.854	1.161–2.961	0.090	0.953	0.682–1.331	0.034	1.838	1.252–2.700	0.199

Abbreviations: OR, odds ratio; CI, confidence interval; P_H, p value based on Q test for between-study heterogeneity; HWE, Hardy–Weinberg equilibrium; CD, conotruncal heart defects; ASD, atrial septal defect; PDA, patent ductus arteriosus; PB, population-based; HB, hospital-based.