Table 5.

Pooled ORs and 95% CIs of the association between fetal 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	19	2697/3434	1.271	1.178–1.372	0.000	1.610	1.374–1.885	0.000	1.258	1.120–1.414	0.057	1.565	1.370–1.788	0.000
Study in HWE	17	2657/3006	1.247	1.155–1.348	0.000	1.537	1.308–1.807	0.000	1.238	1.101–1.392	0.070	1.492	1.302–1.711	0.000
Ethnicity
Caucasian	8	796/1485	1.108	0.970–1.264	0.252	1.233	0.925–1.643	0.296	1.151	0.956–1.385	0.444	1.196	0.920–1.556	0.399
Asian	11	1901/1949	1.358	1.240–1.487	0.000	1.793	1.487–2.162	0.000	1.345	1.164–1.555	0.042	1.695	1.455–1.976	0.000
Types of CHD
All types	15	2197/2877	1.233	1.136–1.339	0.000	1.496	1.259–1.777	0.000	1.230	1.087–1.391	0.099	1.474	1.274–1.707	0.000
CD	3	444/454	1.391	1.148–1.686	0.026	2.053	1.371–3.075	0.021	1.471	1.074–2.015	0.106	1.751	1.249–2.455	0.059
ASD/PDA	1	56/103	2.031	1.255–3.287	–	3.536	1.284–9.735	–	1.901	0.757–4.778	–	3.065	1.529–6.142	–
Source of controls
HB	12	1850/2201	1.322	1.208–1.448	0.000	1.720	1.431–2.067	0.000	1.323	1.146–1.526	0.021	1.633	1.401–1.904	0.000
PB	5	677/902	1.101	0.945–1.283	0.509	1.225	0.871–1.723	0.488	1.101	0.881–1.376	0.688	1.215	0.902–1.638	0.542
Sample size
Small	7	432/679	1.332	1.134–1.565	0.537	1.877	1.294–2.722	0.570	1.501	1.147–1.964	0.875	1.655	1.224–2.237	0.390
Large	12	2265/2755	1.254	1.154–1.363	0.000	1.551	1.306–1.843	0.000	1.221	1.077–1.385	0.013	1.531	1.323–1.772	0.000

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