Table VI.

Case-only analyses of interactions of XPD and XPC polymorphisms with poultry frequency and level of doneness

		CRC cases				Colon cancer cases				Rectal cancer cases			Heterogeneity P-valuec
		ORab	95% CI	P-value		ORab	95% CI	P-value		ORab	95% CI	P-value
	Frequency of cooked poultry consumption per week
	≤2 Servings/>2 servingsd				≤2 Servings/>2 servingsd				≤2 Servings/>2 servingsd
XPC intron 11
C/C	148/66	1.0Ref			96/36	1.0Ref			33/20	1.0Ref
C/A + A/A	277/83	0.7	0.5–1.0	0.040	171/47	0.7	0.4–1.2	0.224	69/28	0.7	0.3–1.4	0.267	0.838
	Level of doneness of poultry from outside
	Light or medium brown/heavily brownede				Light or medium brown/heavily brownede				Light or medium brown/heavily brownede
XPD Lys751Gln
Lys/Lys	166/71	1.0Ref			110/37	1.0Ref			37/26	1.0Ref
Lys/Gln + Gln/Gln	265/71	0.6	0.4–0.9	0.016	160/42	0.8	0.5–1.3	0.335	69/17	0.4	0.2–0.8	0.005	0.075
XPC intron 11
C/C	151/64	1.0Ref			94/38	1.0Ref			35/18	1.0Ref
C/A + A/A	281/78	0.7	0.4–1.0	0.031	177/41	0.6	0.3–1.0	0.031	71/25	0.7	0.3–1.4	0.308	0.694

^aCase-only analyses were done using unadjusted unconditional logistic regression models using the dichotomized exposure as the outcome variable, using individual SNPs as the independent variables to obtain ORs that would be equivalent to IOR.

^bUnadjusted.

^cColon versus rectum heterogeneity test.

^dLess than or equal to two servings as referent group.

^eLight or medium brown as referent group.