TABLE 1.
Baseline characteristics of breast cancer cases and noncases in the Women's Health Initiative
| Cases (n = 190) | Noncases (n = 5260) | P value | |
| Age (y) | 62.7 ± 7.21 | 62.6 ± 6.6 | 0.55 |
| BMI (kg/m2) | 29.1 ± 5.7 | 29.1 ± 6.1 | 0.86 |
| Height (cm) | 161.4 ± 6.3 | 161.0 ± 6.7 | 0.77 |
| Waist circumference (cm) | 88.5 ± 12.9 | 88.6 ± 14.0 | 0.88 |
| Waist-to-hip ratio | 0.82 ± 0.07 | 0.82 ± 0.08 | 0.48 |
| Parity | 2.6 ± 1.7 | 2.7 ± 1.7 | 0.26 |
| Age at menopause (y) | 47.6 ± 6.5 | 46.7 ± 6.8 | 0.14 |
| Alcohol (servings/wk) | 1.6 ± 3.2 | 1.7 ± 4.0 | 0.81 |
| Physical activity (METs)2 | 7.3 ± 10.4 | 10.0 ± 12.9 | 0.0002 |
| Oral contraceptive use, ever (%) | 37.1 | 41.7 | 0.19 |
| Hormone therapy use, ever (%) | 50.3 | 46.6 | 0.31 |
| History of diabetes, yes (%) | 13.6 | 10.4 | 0.19 |
| Age at menarche ≤12 y (%) | 51.0 | 46.9 | 0.38 |
| Age at first birth ≥30 y (%) | 10.1 | 9.0 | 0.27 |
| Breast cancer in a first-degree family member, yes (%) | 16.2 | 15.4 | 0.74 |
| Education, some postcollege (%) | 27.0 | 23.9 | 0.72 |
| Ethnicity, non-Hispanic white (%) | 61.9 | 51.8 | 0.02 |
| Smoking, current smokers (%) | 6.7 | 8.4 | 0.65 |
1
Mean ± SD (all such values).
2
METs, metabolic equivalent tasks (defined as caloric need per kilogram of body weight per hour of activity divided by the caloric need per kilogram of body weight per hour at rest) per hour per week.