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Table 1 Cases and controls included in benign breast disease pathologic specimen collectiona

From: Benign breast disease, recent alcohol consumption, and risk of breast cancer: a nested case–control study

Cases Controls Selection of participants
1,080 4,353 Participants initially selected
-29 -85 Participant died or withdrew from study subsequent to selection
-265 -1,090 We did not pursue collection of specimens, because:
      • participant denied having biopsy or had cyst aspiration only
      • participant could not recall hospital or hospital no longer exists
      • participant denied permission to seek specimens
      • biopsy contained cancer
-379 -1,406 We were unable to obtain requested samples
      • specimens were no longer available or destroyed
      • hospital had no record of the patient or biopsy
      • hospital had no record of the patient or biopsy
-33 -113 Specimens received were not usable for study
      • slides were not of good quality/not evaluable
      • specimens did not contain breast tissue
      • were from wrong person or incorrect date
374 1,659 Eligible participants for whom we collected usable specimens
  1. aNurses' Health Study I (1976 to 1994) and II (1989 to 1995).