. Author manuscript; available in PMC: 2017 May 1.

Published in final edited form as: Cancer Prev Res (Phila). 2016 Mar 7;9(5):396–405. doi: 10.1158/1940-6207.CAPR-15-0380

Table 4.

Urinary levels of [pyridine-D₄]hydroxy acid:total [pyridine-D₄]NNAL ratio by PEITC treatment stratified by GSTM1 and GSTT1 genotypes, The PEITC Intervention Study 2008–2013

GST genotypes	No	Geometric means of [pyridine-D₄]hydroxy acid:total [pyridine-D₄]NNAL ratio				P for interaction^b
GST genotypes	No	Placebo	PEITC	% difference (95% CI)	P value^a	P for interaction^b
GSTM1						0.694

null	37	0.423	0.397	−6.2 (−16.5, 5.3)	0.284
Present	45	0.483	0.441	−8.8 (−15.9, −1.1)	0.031

GSTT1						0.574
null	19	0.387	0.344	−11.1 (−19.7, −1.6)	0.037
Present	63	0.478	0.446	−6.7 (−14.2, 1.5)	0.111

GSTM1 & GSTT1						0.436
Both null	12	0.373	0.314	−15.6 (−26.7, −2.9)	0.039
Only one gene present	32	0.445	0.431	−3.1 (−14.6, 9.9)	0.623
Both genes present	38	0.496	0.450	−9.4 (−17.4, −0.6)	0.045

2-sided P values were derived from the mixed models to test PEITC treatment effect within specific GST genotype group.

2-sided P values were derived from the mixed models to test the modifying effect of genotype on the PEITC’s effect on the [pyridine-D₄]hydroxy acid:total [pyridine-D₄]NNAL ratio.