HFE Gene Variants Modify the Association between Maternal Lead Burden and Infant Birthweight: A Prospective Birth Cohort Study in Mexico City, Mexico

Table 5 Adjusted regression coefficients for effect modification of HFE or TF genotype upon tibia lead's adverse association with birthweight^a

Model	Genotype	Genotype Variant	Tibia Lead	Interaction Term
1	Infant HFE H63D	-127.5**	-6.5**	4.5
2	Infant TF P570S	34.9	-5.8**	0.9
3	Maternal HFE H63 D ^b	-62.7	-3.0	-10.3**
4	Maternal TF P570 S ^b	-60.8	-5.7**	6.8
5	Maternal/Infant HFE H63 D Interactions
	H63_Inf. Wildtype/H63_Mat.Wildtype	Referent
	H63_Inf. Wildtype/H63D_Mat.Variant	143.0	-4.5*	-28.7**
	H63D_Inf. Variant/H63_Mat.Wildtype	-64.2		6.2
	H63D_Inf. Variant/H63D_Mat.Variant	-177.2**		-6.0
6	Maternal/Infant TF P570 S Interactions
	TF_Inf. Wildtype/TF_Mat.Wildtype	Referent
	TF_Inf. Wildtype/TF_Mat.Variant	-51.7	-7.2**	10.3
	TF_Inf. Variant/TF_Mat.Wildtype	66.7		-4.5
	TF_Inf. Variant/TF_Mat.Variant	-40.5		9.3

^aAll models are adjusted for maternal age, years of maternal education, infant gender, maternal arm circumference, gestational age, smoking status during pregnancy, maternal hemoglobin one month post-partum, and parity.
^bAll models additionally adjusted for maternal age², and dummy variables for maternal education (years of education: <8, 8 -11, 11>) to account for the non-linear nature of these covariates.
* P-value < 0.1, ** P-value < 0.05
Infant - Inf., Maternal - Mat.

ISSN: 1476-069X