Table 1.

Characteristics of the cohort study of BRCA1/2 mutation carriers

Total cohort (N = 1,601), n (%)Women with breast cancer (N = 853), n (%)Unaffected women (N = 748), n (%)
Person-years of follow-up65,675
Age at interview, mean (SD)46.7 (12.0)50.1 (10.7)42.9 (12.3)
Age at diagnosis/censure
    Mean (SE)41.5 (10.1)41.6 (9.0)41.4 (11.2)
Mutation
    BRCA11,187 (74.1)602 (70.6)585 (78.2)
    BRCA2414 (25.9)251 (29.4)163 (21.8)
Year of birth
    <1940223 (11.9)151 (17.7)72 (9.6)
    1940 to <1950356 (22.2)232 (27.2)124 (16.6)
    1950 to <1960494 (30.9)296 (34.7)198 (26.5)
    ≥1960528 (33.0)174 (20.4)354 (47.3)
Country group*
    1358 (22.4)179 (21.0)179 (23.9)
    2171 (10.7)81 (9.5)90 (12.0)
    3539 (33.7)299 (35.1)231 (30.9)
    4542 (33.9)294 (34.5)248 (33.2)
Age at menarche
    ≤11275 (17.2)130 (17.4)145 (17.0)
    12-141,060 (66.2)506 (67.6)554 (65.0)
    ≥15243 (15.2)101 (13.5)142 (16.6)
    Unknown23 (1.4)11 (1.5)12 (1.4)
Menopausal status
    Premenopausal1,228 (76.7)665 (78.0)563 (75.3)
    Postmenopausal
        Natural150 (3.5)78 (9.1)72 (9.6)
        Oophorectomy55 (9.4)17 (2.0)38 (5.1)
        Other reasons31 (1.9)15 (1.8)16 (2.1)
    Unknown137 (8.5)78 (9.1)59 (7.9)
Number of full-term pregnancies
    0304 (19.0)145 (17.0)159 (21.3)
    1239 (14.9)137 (16.1)102 (13.6)
    2621 (38.8)329 (38.6)292 (39.0)
    3297 (18.6)161 (18.9)136 (18.2)
    ≥4138 (8.6)80 (9.4)58 (7.8)
    Unknown2 (0.1)1 (0.0)1 (0.1)
HRT use
    Never1,449 (90.5)790 (92.6)659 (88.1)
    Ever152 (9.5)63 (7.4)89 (11.9)
  • * Group 1: Austria, Belgium, Germany, Holland, Hungary; group 2: Iceland, Denmark, Sweden; group 3: France, Spain, Italy, Quebec; group 4: United Kingdom/Eire.