Variation in breast cancer risk associated with factors related to pregnancies according to truncating mutation location, in the French National BRCA1 and BRCA2 mutations carrier cohort (GENEPSO)

Lecarpentier, Julie; Noguès, Catherine; Mouret-Fourme, Emmanuelle; Gauthier-Villars, Marion; Lasset, Christine; Fricker, Jean-Pierre; Caron, Olivier; Stoppa-Lyonnet, Dominique; Berthet, Pascaline; Faivre, Laurence; Bonadona, Valérie; Buecher, Bruno; Coupier, Isabelle; Gladieff, Laurence; Gesta, Paul; Eisinger, François; Frénay, Marc; Luporsi, Elisabeth; Lortholary, Alain; Colas, Chrystelle; Dugast, Catherine; Longy, Michel; Pujol, Pascal; Tinat, Julie; Lidereau, Rosette; Andrieu, Nadine

doi:10.1186/bcr3218

Table 2 Risk of breast cancer associated with full-term pregnancies and breast feeding.

From: Variation in breast cancer risk associated with factors related to pregnancies according to truncating mutation location, in the French National BRCA1 and BRCA2 mutations carrier cohort (GENEPSO)

Reproductive Factors		One woman per family cohort: 39,666 person-years of follow-up					*BRCA1*mutation carriers: 25,045 person-years of follow-up					*BRCA2*mutation carriers: 14,621 person-years of follow-up
		Person-years^a	No. of cases^a	HR	95% CI	Pvalue	Person-years^a	No. of cases^a	HR	95% CI	Pvalue	Person-years^a	No. of cases^a	HR	95% CI	Pvalue
Parity^b
	Nulliparous	25,333	58	1.00			16,215	38	1.00			9,118	20	1.00
	Parous	14,333	321	0.77	0.53-1.13		8,830	202	0.76	0.49-1.19		5,503	119	0.78	0.39-1.55
No. of full-term pregnancies^b
	0	25,333	58	1.00			16,215	38	1.00			9,118	20	1.00
	1	4,435	90	1.10	0.72-1.68		2,777	58	1.04	0.63-1.72		1,658	32	1.24	0.59-2.61
	2	5,640	138	0.79	0.52-1.20		3,540	87	0.81	0.50-1.30		2,100	51	0.73	0.35-1.55
	≥3	4,243	92	0.51	0.33-0.81	<10^-3	2,498	56	0.52	0.31-0.89	0.02	1,745	36	0.49	0.22-1.10	0.08
	Trend			0.77	0.68-0.88	<10^-3			0.78	0.67-0.91	<10^-3			0.74	0.58-0.95	0.02
No. of full-term pregnancies by attained age^b
	0	25,333	58	1.00			16,215	38	1.00			9,118	20	1.00
	1-2 before age 40	8,146	131	1.05	0.68-1.63		5,169	88	1.04	0.62-1.77		2,977	43	1.12	0.53-2.37
	≥3 before age 40	2,303	40	0.82	0.48-1.41		1,414	29	0.88	0.46-1.66		889	11	0.64	0.23-1.75
	1-2 after age 40	1,929	97	0.70	0.36-1.36		1,148	57	0.70	0.32-1.50		781	40	0.61	0.19-1.99
	≥3 after age 40	1,940	52	0.35	0.17-0.70	<10^-3	1,084	27	0.34	0.15-0.76	0.01	856	25	0.36	0.11-1.16	0.09
Age at first full-term pregnancy^c
	< 20 years	1,866	39	1.00			1,217	27	1.00			649	12	1.00
	20-24 years	7,158	152	0.91	0.55-1.50		4,296	93	0.91	0.52-1.61		2,862	59	0.87	0.32-2.34
	25-29 years	3,994	85	0.62	0.36-1.06	0.08	2,492	53	0.57	0.31-1.06	0.08	1,502	32	0.63	0.22-1.80
	≥30 years	1,315	45	0.67	0.36-1.23		825	29	0.64	0.32-1.31		490	16	0.65	0.20-2.13
	Nulliparous	25,333	58	0.41	0.20-0.85	0.02	16,215	38	0.43	0.19-0.97	0.04	9,118	20	0.35	0.09-1.40
Breast-feeding^c
	Never	5,962	131	1.00			3,644	87	1.00			2,318	44	1.00
	Ever	7,875	182	1.02	0.76-1.36		4,840	111	0.93	0.66-1.30		3,035	71	1.45	0.84-2.51
	Nulliparous	25,333	58	0.61	0.37-1.02	0.06	16,215	38	0.62	0.33-1.14		9,118	20	0.53	0.21-1.30

^a Not including missing data. ^b Adjusted for menopausal status (yes, no), oral contraceptives (never, ever), and gene mutated (BRCA1, BRCA2). ^c Adjusted for parity (0, 1, 2, ≥3), menopausal status (yes, no), oral contraceptives (never, ever), and gene mutated (BRCA1, BRCA2). HR hazard ratio; CI confidence interval, No., number.

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