Table 1.

Characteristics of premenopausal Caucasian and African American women with genotype information from NIEHS UFS

CharacteristicsCaucasians (n = 402), n (%)African Americans (n = 582), n (%)
Age (y)
    35-39137 (34.1)219 (37.6)
    40-44135 (33.6)205 (35.2)
    ≥45130 (32.3)158 (27.1)
Education
    High school12 (3.0)121 (20.8)*
    Some postsecondary33 (8.2)265 (45.5)
    College degree133 (33.1)123 (21.1)
    Graduate degree217 (54.0)68 (11.7)
    Missing7 (1.7)5 (0.9)
Current oral contraceptives37 (9.2)28 (4.8)
Parity
    0236 (58.7)120 (20.6)
    154 (13.4)134 (23.0)
    291 (22.6)194 (33.3)
    ≥321 (5.2)134 (23.0)
Body mass index
    Underweight-normal weight (<25)236 (58.7)147 (25.3)
    Overweight (25 to <30)95 (23.6)178 (30.6)
    Obese (≥30)71 (17.7)257 (44.2)
Smoking status
    Current smoker31 (7.7)172 (29.6)
    Former smoker139 (34.6)133 (22.9)
    Never smoked232 (57.7)277 (47.6)
Alcohol intake (past year)
    <0.5 drinks/wk60 (14.9)300 (51.5)
    ≥0.5 drinks/wk314 (78.1)245 (42.1)
    Missing28 (7.0)37 (6.4)

Mean (SD)
Mean (SD)
Plasma IGF-I (ng/mL)172 (58.7)165 (74.0)
Plasma IGFBP-3 (ng/mL)4,524 (822.3)4,085 (859.7)
  • * Includes 11 women with less than high school education.

  • n missing: oral contraceptives: 3 Caucasians and 4 African Americans; Plasma IGF-I and IGFBP-3: 1 Caucasian and 8 African Americans.