Table 1.

Characteristics of cases and controls in the MEC breast cancer nested case–control study

Cases (n = 706)Controls (n = 706)
Age at blood draw, y, mean (SD)a67.8 (7.4)67.8 (7.4)
Hours fasting before blood draw, mean (SD)a12.9 (5.6)12.9 (5.5)
Ethnicity, n (%)a
 African American106 (15.0)106 (15.0)
 Native Hawaiian68 (9.6)68 (9.6)
 Japanese American248 (35.1)248 (35.1)
 Latino132 (18.7)132 (18.7)
 White152 (21.5)152 (21.5)
Years of education, mean (SD)13.6 (3.1)13.7 (3.0)
Positive first-degree family history of breast cancer, n (%)105 (14.9)81 (11.5)
BMI (kg/m2), mean (SD)26.7 (5.2)26.1 (5.5)
Age at menarche, mean (SD)13.0 (1.6)13.1 (1.6)
Age at natural menopause, mean (SD)49.5 (4.6)49.1 (4.7)
Age at first live birth, mean (SD)23.6 (4.6)23.4 (4.5)
Parity, n (%)
 Nulliparous86 (12.3)69 (9.9)
 177 (11.0)77 (11.0)
 2–3339 (48.4)317 (45.4)
 ≥ 4199 (28.4)236 (33.8)
Current hormone replacement therapy use, n (%)*193 (27.3)193 (27.3)
Smoking history, n (%)
 Never smoker385 (55.1)405 (57.9)
 Former smoker222 (31.8)222 (31.8)
 Current smoker92 (13.2)72 (10.3)
Moderate or vigorous physical activity (h/d), mean (SD)1.2 (1.3)1.2 (1.3)
Alcohol consumption (ethanol g/d), mean (SD)4.9 (15.8)3.9 (13.1)
Leptin, ng/mL, median (25th–75th percentile)22.9 (13.4–38.4)19.0 (10.5–35.1)
Adiponectin, μg/mL, median (25th–75th percentile)8.9 (5.6–15.3)10.0 (5.6–16.1)
Leptin:adiponectin ratio, median (25th–75th percentile)2.7 (1.2–5.6)2.2 (0.8–5.2)
CRP, mg/L, median (25th–75th percentile)2.2 (1.2–4.4)1.9 (0.9–4.0)
Blood draw to diagnosis, y, median (25th–75th percentile)3.3 (1.6–5.0)
SEER stage, n (%)
 Localized465 (65.9)
 Regional158 (22.4)
 Distant metastasis20 (2.8)
Size, cm, n (%)
 <2.0300 (42.5)
 2.0–5.0126 (17.8)
 >5.019 (2.7)
Axillary node status, n (%)
 N0465 (65.9)
 N1155 (22.0)
Grade, n (%)
 I156 (22.1)
 II275 (39.0)
 III177 (25.1)
Receptor status, n (%)
 ER+498 (70.5)
 PR+411 (58.2)

NOTE: Cases and controls were matched on age of birth (±1 year), location (HI or CA), ethnicity, date of blood draw (±6 months), time of blood draw (±2 hours), hours fasting before blood draw (<6, 6–<8, 8–<10, ≥10), and hormone replacement therapy use at blood draw (current vs. not current).

  • aMatching variables.