Table 1 Baseline characteristics of the study participants
|
Case (n = 473) |
Control (n = 501) | p-value | |
|---|---|---|---|
| Age (years) | 45.8 ± 10.3 | 43.9 ± 11.2 | 0.002 |
| BMI (kg/m2) | 28.0 ± 5.1 | 28.8 ± 6.0 | 0.01 |
| Physical activity (MET-h/week) | 22.7 ± 40.2 | 29.4 ± 43.9 | 0.006 |
| Age at menarche (years) | 13.0 ± 2.5 | 12.9 ± 2.7 | 0.28 |
| Menopausal status (%) | |||
| Premenopausal | 309 (66.1) | 326 (66.4) | 0.94 |
| Postmenopausal | 158 (33.8) | 165 (33.6) | |
| Educational level (%) | |||
| Un university | 394 (84.3) | 411 (84.0) | 0.89 |
| University | 73 (15.6) | 78 (15.9) | |
| Marital status (%) | |||
| Married | 437 (93.7) | 462 (94.2) | 0.74 |
| Unmarried/divorced/widowed | 29 (6.2) | 28 (5.7) | |
| Family history of breast cancer (%) | 46 (9.8) | 7 (1.4) | < 0.001 |
| Oral contraceptive use (%) | 244 (53.0) | 259 (61.2) | 0.01 |
| Current smoker (%) | 18 (3.8) | 25 (5.1) | 0.34 |
| Alcohol use (%) | 12 (2.5) | 30 (5.9) | 0.008 |
| Postmenopausal hormone use (%) | 2 (0.42) | 10 (2.00) | 0.02 |
| Parity | |||
| Nulliparous/missing | 210 (44.1) | 215 (42.9) | 0.90 |
| 1 | 42 (8.8) | 51 (10.1) | |
| 2–3 | 149 (31.3) | 155 (30.9) | |
| ≥ 4 | 75 (15.7) | 80 (15.9) |