Table 1.

Characteristic of cases and controls

Characteristic	Cases n = 128	Controls n = 269	p value
Date of birth (mean) (range)	1965.2 (1947–82)	1964.5 (1946–81)	0.44
Year of diagnosis (range)	1997.3 (1985–2009)	1997.8 (1985–2011)	0.47
Age of breast cancer (range)	32.5 (25–42)	33.8 (26–44)	0.009
Date of baseline questionnaire (range)	2,003.5 (1996–2011)	2,003.7 (1996–2012)	0.84
Mutation n (%)
BRCA1	106 (81.3 %)	227 (84.4 %)	Matched
BRCA2	24 (18.8 %)	42 (15.6 %)
Place of residence	96 (75.0 %)	210 (78.1 %)	Matched
North America	20 (15.6 %)	43 (16.0 %)
Poland	12 (9.4 %)	16 (6.0 %)
Others
Parous
No	0	78 (29.5 %)	0.62
Yes	128 (100 %)	191 (71.0 %)
Mean Parity	2.1(1–5)	2.0 (1–4)
Age of menarche (years)	12.8 (9–17)	12.8 (10–21)	0.73
Age at first birth (years)	30.7 (18–42)	25.6 (18–33)	< 0.0001
Age at last birth (years)	35.0 (27–44)	28.7 (20–38)	< 0.0001
Time from diagnosis to last childbirth (years)	2.4 (0–13)	NA	< 0.0001
Salpingo-oophorectomy after breast cancer diagnosis
No	55 (43.0 %)	127 (47.2 %)
Yes	73 (57.0 %)	142 (52.8 %)	0.43
Vital status
Alive	120 (92.8 %)	246 (91.5 %)
Dead	8 (6.3 %)	23 (8.6 %)	0.42
Cause of death
Breast cancer	7	19
Unknown	1	4