Table 1.

Characteristics of cases and controls at time of blood collection

ControlsCases
Sample size339117
Age (mean, SD), y*57 (7)57 (7)
Age at diagnosis (mean, SD), yNA65 (8)
Postmenopausal at blood collection (%)*6162
Postmenopausal at time of diagnosis (%)*8788
Use of postmenopausal hormones within 3 mo of blood collection (%)*4547
Height (mean, SD), inches65 (4)65 (3)
BMI (mean, SD), kg/m225 (5)25 (5)
Age at menarche (mean, SD), y13 (1)13 (1)
Parous (%)9691
Number of live births (mean, SD)§3 (1)3 (2)
Age at first birth (mean, SD), y§25 (3)25 (4)
Ever breastfed (%)§6761
Duration of oral contraceptive use (mean, SD), mo55 (47)44 (40)
Tubal ligation (%)2018
Hysterectomy (%)2126
Age at natural menopause (mean, SD), y51 (3)51 (3)
Number of lifetime ovulations (mean, SD)379 (67)389 (64)
Weekly use of perineal talcum powder (%)2226
Family history of breast cancer (%)99
Family history of ovarian cancer (%)39

Abbreviations: NA, not applicable; BMI, body mass index.

  • *Cases and controls were matched on these factors.

  • For controls, menopausal status at the time of the case's ovarian cancer diagnosis.

  • Among postmenopausal women at blood collection.

  • §Among parous women.

  • Among women who ever used OC for at least 3 months.