Table 5.

Pooled RR (95% CI) for the association between regular talc use and ovarian cancer risk, stratified by genotype, in the NECC and the NHS

	All cancers			Serous invasive cancers			Cases and controls in pooled analysis
	All cancers			Serous invasive cancers						All cases		Serous invasive		Controls
		Regular talc use			Regular talc use			Regular talc			Regular talc		Regular talc
		No	Yes	No	Yes	No	Yes	No	Yes	No	Yes
Gene/stratum
GSTM1 genotype
Present (+)	1.0 (reference)	1.6 (1.2-2.0)	1.0 (reference)	2.0 (1.4-2.8)	480	189	173	90	646	165
Null (-)	1.0 (reference)	1.3 (1.0-1.6)	1.0 (reference)	1.4 (1.0-1.9)	498	179	190	76	690	198
P_interaction*	0.13		0.08
GSTT1 genotype
Present (+)	1.0 (reference)	1.2 (1.0-1.5)	1.0 (reference)	1.5 (1.2-2.0)	785	278	288	129	1,035	301
Null (-)	1.0 (reference)	2.1 (1.4-3.2)	1.0 (reference)	2.4 (1.4-4.0)	194	87	71	38	300	67
P_interaction*	0.03		0.18
NAT2 genotype
Rapid/intermediate acetylator	1.0 (reference)	1.5 (1.1-2.0)	1.0 (reference)	1.9 (1.2-2.8)	330	128	123	57	459	113
Slow acetylator	1.0 (reference)	1.4 (1.1-1.8)	1.0 (reference)	1.6 (1.2-2.1)	552	217	204	96	819	233
P_interaction*	0.60		0.58
GSTM1/GSTT1 genotype^†
GSTM1+, GSTT1+	1.0 (reference)	1.4 (1.0-1.8)	1.0 (reference)	1.7 (1.2-2.5)	378	142	136	68	479	140
GSTM1-, GSTT1+	1.0 (reference)	1.2 (0.9-1.5)	1.0 (reference)	1.4 (0.9-1.9)	400	135	151	60	541	154
GSTM1+, GSTT1-	1.0 (reference)	2.8 (1.6-5.0)	1.0 (reference)	4.8 (2.1-11)	98	47	34	22	158	24
GSTM1-, GSTT1-	1.0 (reference)	1.6 (0.9-2.9)	1.0 (reference)	1.4 (0.6-3.1)	94	40	36	16	138	41
P_interaction*	0.03		0.09

NOTE: NECC: unconditional logistic regression adjusted for age, study center, duration of oral contraceptive use (months), parity (continuous), tubal ligation, BMI (kg/m², continuous), and duration of PMH use (months); NHS: unconditional logistic regression adjusted for age (months), menopausal status at diagnosis (post, pre/dubious), DNA source, duration of oral contraceptive use (months), parity (continuous), tubal ligation, BMI (kg/m², continuous), and duration of PMH use (months). P values for tests for heterogeneity comparing the NECC and NHS results were all >0.36.
↵* P values for interaction based on likelihood ratio test comparing unconditional logistic regression models with and without gene-talc interaction terms.
↵† NHS analysis adjusted for age, menopausal status at diagnosis, and DNA source only to improve stability of estimates.