Table 2:
Baseline characteristics of women from the Women’s Health Initiative study
| Characteristic | Breast cancer |
|
|---|---|---|
| Yes (N=9,396) | No (N=127,887) | |
|
| ||
| Age at entry (yrs.) | ||
| Median (IQR) | 62 (57–68) | 63 (57–69) |
| Race and ethnicity: N (%) | ||
| African-American | 607 (6.3) | 11,282 (8.8) |
| Asian | 180 (1.9) | 2,721 (2.1) |
| American Indian and Alaskan native | 66 (0.7) | 1,007 (0.8) |
| Native Hawaiian and other Pacific Islander | 82 (0.9) | 1,400 (1.1) |
| Spanish and Latina | 174 (1.9) | 3,953 (3.1) |
| White (not of Hispanic origin) | 8,156 (86.8) | 104,174 (81.5) |
| Missing | 147 (1.6) | 3,350 (2.6) |
| Education: N (%) | ||
| Graduate School /Some graduate school | 1,679 (17.9) | 28,874 (22.6) |
| Age at first live birth (yrs.): N (%); <12) | 1,009 (10.7) | 16,383 (12.8) |
| Family history: N (%) | 2,180 (23.2) | 21,872 (17.1) |
| Age at menarche (yrs.): N (%); <12) | 2,162 (23.0) | 27,413 (21.4) |
| Parity: (N (%); nulliparous) | 1,246 (13.3) | 14,851 (11.6) |
| Breastfed: N (%) | 4,813 (51.2) | 65,226 (51.0) |
| Age at menopause (yrs.): (N (%); ≥55) | 1,307 (17.8) | 16,405 (12.8) |
| Ever had mammogram: N (%) | 9,156 (97.5) | 122,551 (95.8) |
| Unopposed estrogen: N (%) | 3.126 (33.3) | 44,966 (35.2) |
| Estrogen/progesterone combined therapy: N (%) | 3,110 (33.1) | 32,968 (25.8) |
| Oral contraceptive: N (%) | 4,175 (44.4) | 53,352 (41.7) |
| Alcohol serving/week) | ||
| Median (IQR) | 0.4 (0.0–3.4) | 0.4 (0.0–2.7) |
| Health eating index | ||
| Median (IQR) | 65.8 (58.3–72.9) | 65.6 (57.9–72.7) |
| Physical activity (Met-hours/week) | ||
| Median (IQR) | 7.5 (1.5–17.3) | 7.5 (1.5–17.5) |
| BMI (kg/m2) | ||
| Median (IQR) | 27.0 (23.9–31.1) | 26.8 (23.7–30.8) |
| WC (cm.) | ||
| Median (IQR) | 85.0 (76.5–95.0) | 84.0 (76.0–94.2) |
| WHR | ||
| Median (IQR) | 0.80 (0.76–0.85) | 0.80 (0.76–0.86) |
| Smoking status: (N (%); current | 594 (6.3) | 8,968 (7.0) |
| Ikeda predicted REE | ||
| Median (IQR) | 1,278 (1,191–1,387) | 1,263 (1,177–1,374) |
| Livingston predicted REE | ||
| Median (IQR) | 1,276.5 (1,184.5–1,378.8) | 1,260.3 (1,169.8–1,366.8) |
| Mifflin predicted REE | ||
| Median (IQR) | 1,262.5 (1,160.3–1,381.6) | 1,241.5(1,138.6–1,363.0) |
Abbreviations: BMI = body mass index, WC= waist circumference, WHR= waist to hip; Met=metabolic equivalent, IQR= interquartile range