Table 1.

Characteristics of African-American study participants, by case-control status

Cases (n = 239)*Controls (n = 249)*P
Age
    Mean (SD)55.6 (11.5)55.3 (11.6)0.79
    Median (interquartile range)54 (47-64)54 (46-65)0.78
Menopausal status
    Premenopausal72 (30.1%)82 (32.9%)
    Postmenopausal146 (61.1%)146 (58.6%)0.80
    Undetermined21 (8.8%)21 (8.4%)
Education (y)
    <1242 (17.6%)46 (18.5%)
    1253 (22.2%)64 (25.7%)
    13-1694 (39.3%)101 (40.6%)
    ≥1750 (20.9%)38 (15.3%)0.41
First-degree family history
    Yes35 (14.6%)32 (12.8%)
    No204 (85.4%)217 (87.2%)0.57
Benign breast disease
    Yes61 (25.5%)38 (15.4%)
    No178 (74.5%)209 (84.6%)0.006
Age at menarche
    <1252 (21.9%)55 (22.4%)
    12-13133 (55.9%)130 (52.9%)
    ≥1453 (22.3%)61 (24.8%)0.76
Age at menopause
    Mean (SD)46.4 (7.02)46.4 (8.08)0.97
    Median (interquartile range)48 (44-51)48 (43-51)0.78
Number of full-term pregnancies
    Nulliparous44 (18.4%)34 (13.7%)
    142 (17.6%)47 (18.9%)
    254 (22.6%)55 (22.1%)
    343 (18.0%)48 (19.3%)
    ≥456 (23.4%)65 (26.1%)0.68
Age at first full-term pregnancy
    <2083 (42.6%)93 (43.3%)
    20-2459 (30.3%)79 (36.7%)
    25-2927 (13.9%)27 (12.6%)
    ≥3026 (13.3%)16 (7.4%)0.18
History of oral contraceptive use
    Yes160 (67.5%)163 (66.0%)
    No77 (32.5%)84 (34.0%)0.72
History of hormone replacement therapy use (postmenopausal women)
    Yes70 (48.0%)83 (58.0%)
    No76 (52.0%)60 (42.0%)0.09
Body mass index in premenopausal women
    Mean (SD)30.1 (6.21)32.4 (8.20)0.05
    Median (interquartile range)29.3 (25.0-34.5)30.5 (25.5-39.9)0.11
    <2518 (25.0%)16 (19.5%)
    25-2920 (27.8%)23 (28.1%)
    ≥3034 (47.2%)43 (52.4%)0.69
Body mass index in postmenopausal women
    Mean (SD)31.2 (6.34)31.5 (7.17)0.71
    Median (interquartile range)30.5 (26.6-35.2)30.8 (26.5-34.6)0.97
    <2524 (16.6%)26 (17.8%)
    25-2944 (30.3%)40 (27.4%)
    ≥3077 (53.1%)80 (54.8%)0.85
  • * The numbers in the table do not add up due to missing values.