GSTM1 and APE1 genotypes affect arsenic-induced oxidative stress: a repeated measures study

Table 4 The effect of quartiles of arsenic on logged urinary 8-OHdG (μg/l) by GSTM1 genotype (N = 290)

	GSTM1 positive		GSTM1 null		Wald p-value^†	LRT p-value^††
Model*	β	95% CI	β	95% CI
Total urinary arsenic quartile (μg/l)						0.007
1.35 – 13.3	reference		reference
>13.3 – 22.6	-0.12	(-0.46, 0.22)	0.84	(0.27, 1.42)	0.004
>22.6 – 47.9	-0.06	(-0.43, 0.31)	0.98	(0.33, 1.66)	0.005
>47.9 – 431.3	-0.15	(-0.60, 0.30)	0.85	(0.27, 1.44)	0.004
Drinking water arsenic quartile (μg/l)						0.69
0.5	reference		reference
>0.50 – 1.5	-0.05	(-0.42, 0.31)	0.26	(-0.41, 0.93)	0.43
>1.5 – 81.7	0.29	(-0.11, 0.69)	0.15	(-0.46, 0.75)	0.69
>81.7 – 591	-0.21	(-0.66, 0.24)	0.002	(-0.74, 0.75)	0.63
Toenail arsenic quartile (μg/g)						0.69
0.2 – 0.6	reference		reference
>0.6 – 0.8	-0.19	(-0.71, 0.33)	-0.09	(-0.93, 0.75)	0.83
>0.8 – 1.6	-0.36	(-0.87, 0.14)	-0.22	(-1.06, 0.63)	0.77
>1.6 – 10.2	-0.49	(-1.00, 0.03)	0.05	(-0.76, 0.87)	0.26

*Main effects are from three random effects Tobit models adjusted for logged creatinine, BMI, age, betelnut chewing, environmental tobacco smoke, and education (secondary or higher vs primary or less), and hOGG1 and APE1 genotypes.
^† significance test for individual interaction terms.
^†† significance test for the entire group of arsenic quartile by gene interactions

ISSN: 1476-069X