Table 1

Baseline characteristics of 87 premenopausal women who donated two follicular and two luteal blood samples over approximately a 1-year period

CharacteristicsMean (SD)
At time of first blood draw
 Age (years)41.3 (4.1)
 BMIa (kg/m2)25.8 (5.7)
Time between blood sample collections (months)11.3 (3.1)
Percentage
From previous NHSII questionnaires
 Current cigarette smokingb5.7
 Age at menarchec
  <10 yr14.9
  11–12 yr40.2
  13–14 yr36.8
  15+ yr8.0
 Parityb
  Nulliparous17.2
  112.6
  239.1
  3–428.7
  5+2.3
 Family history of breast cancerc6.9
 Personal history of benign breast diseaseb28.7
  • a BMI, body mass index.

  • b 1993 questionnaire.

  • c 1989 questionnaire.