Table 2. Selected characteristics of subjects with and without breast cancer.
| Cases subjects (n=1009) | Controls subjects (n=1009) | P-value a | |
|---|---|---|---|
| Age at interview (years) | 48.4±10.3 | 48.4±10.3 | 0.96 |
| Resident in rural area | 471 (46.7) | 475 (47.1) | 0.86 |
| Education | <0.01 | ||
| No formal education | 183 (18.1) | 151 (15.0) | |
| Primary | 290 (28.7) | 289 (28.6) | |
| Secondary | 395 (39.2) | 376 (37.3) | |
| Tertiary | 141 (14.0) | 193 (19.1) | |
| Body mass index (kg m–2, 5-years ago) | <0.01 | ||
| <25 | 794 (78.7) | 841 (83.3) | |
| ⩾25 | 215 (21.3) | 168 (16.7) | |
| No. of delivery of full-term pregnancy | 1.70±1.2 | 1. 71±1.2 | 0.94 |
| No. of children breastfed | 1.61±1.1 | 1.67±1.2 | 0.24 |
| Oral contraceptive use (year) | 3.1±5.1 | 2.3±3.6 | 0.02 |
| Hormone replacement therapy (year) | 1.7±3.4 | 1.4±1.6 | 0.67 |
| Postmenopausal status | 337 (33.4) | 338 (33.5) | 0.96 |
| Breast cancer in first-degree relatives | 35 (3.5) | 17 (1.7) | 0.01 |
| Alcohol consumption | <0.001 | ||
| Abstainers | 660 (65.4) | 529 (52.4) | |
| Ex-drinkers | 15 (1.5) | 10 (1.0) | |
| Current drinkers | 334 (33.1) | 470 (46.6) | |
| Alcohol intake (ethanol, g per day) | <0.001 | ||
| >0–<5 | 225 (67.4) | 366 (77.9) | |
| 5–<10 | 28 (8.4) | 42 (8.9) | |
| 10–<20 | 12 (3.6) | 13 (2.8) | |
| 20–<30 | 45 (13.5) | 43 (9.1) | |
| ⩾30 | 39 (11.7) | 16 (3.4) | |
| Tea drinking | 451 (44.7) | 661 (65.5) | <0.001 |
| Tobacco smoking | 20 (2.0) | 14 (1.4) | 0.30 |
| Physical activity (weekly MET-hour) | 58.3±71.2 | 60.1±59.1 | 0.54 |
| Folate intake (μg per day) | 577.5±168.5 | 579.2±164.7 | 0.82 |
| Energy intake (kcal per day) | 2184.0±569.3 | 2084.3±506.3 | <0.001 |
Abbreviation: MET=metabolic equivalent task.
a
Two-sided, t-test for continuous variables and χ2 test for categorical variables.
Values expressed as mean±s.d. or number (percent).