Table 1.

Characteristics of the study populations

KConFabBGSaEPICb
ControlsCasesControlsCasesControlsCases
N225166253253291248
Age at blood draw, mean (range), y60 (33–83)50 (21–91)54 (23–82)54 (23–82)52 (33–76)52 (33–76)
Family history, n (%)
 Yes0 (0)166 (100)51 (20)69 (27)24 (14)23 (18)
 No225 (100)0 (0)201 (80)183 (73)144 (86)108 (82)
Menopausal status at blood draw, n (%)
 Premenopausal37 (17)101 (65)135 (61)134 (62)145 (50)127 (50)
 Postmenopausal183 (83)54 (35)87 (39)83 (38)146 (50)121 (50)
Time from blood collection to diagnosis, mean (range), mo45 (1–140)18 (<1–59)55 (24–108)
Age at diagnosis, mean (range)52 (29–88)55 (23–84)57 (37–80)
  • aCases were individually matched to controls for recruitment source, year of completion of the baseline questionnaire at enrolment, ethnicity, availability of blood sample, date of birth within 12 months, and duration that the blood sample was in the mail.

  • bCases and controls were selected within strata of menopausal status (pre and post) and individually matched on age, recruitment centre, and date and time of blood collection.