Associations between prenatal exposure to cadmium and lead with neural tube defect risks are modified by single-nucleotide polymorphisms of fetal MTHFR and SOD2: a case–control study

Table 5 Interaction between single-nucleotide polymorphisms (SNPs) in fetal SOD2 and MTHFR and cadmium (Cd) exposure on NTD risk

SNP and genotype	Cd level	Cases	Controls	cOR (95% CI)	P	aOR (95% CI)	P ^a
*SOD2* rs4880
AA	Low	61	54	1		1
AA	High	64	50	1.13 (0.67–1.91)	0.638	1.08 (0.63–1.87)	0.776
GG&AG	Low	7	25	1		1
GG&AG	High	23	15	5.48 (1.90–15.82)	0.002	3.77 (1.15–12.36)	0.028
Multiplicative interaction ^b				4.83 (1.48–15.76)	0.009	4.43 (1.30–15.07)	0.017
Additive interaction ^c				0.77 (0.46–1.09)	< 0.0001	0.76 (0.42–1.11)	< 0.0001
*MTHFR* rs1801133
CC	Low	11	11	1
CC	High	7	13	0.54 (0.16–1.87)	0.329	0.87 (0.23–3.32)	0.834
CT & TT	Low	57	68	1
CT & TT	High	80	51	1.87 (1.14–3.08)	0.014	1.55 (0.91–2.64)	0.106
Multiplicative interaction ^b				3.48 (0.91–13.25)	0.068	2.68 (0.67–10.74)	0.164
Additive interaction ^c				0.74 (0.27–1.20)	0.0019	0.64 (0.02–1.25)	0.042

Abbreviations: cOR crude odds ratio, aOR adjusted odds ratio
^aAdjusted for folic acid supplementation
^bMultiplicative interaction was measured by a cross-product term by genotype and metal level
^cAdditive interaction was measured by the relative excess risk of interaction (RERI)

ISSN: 1476-069X