Characteristics | Case (n = 373) | Control (n = 657) | P-value |
---|---|---|---|
Median (IQR)/N (%) | Median (IQR)/N (%) | ||
Age at baseline (years) | 50.6 (44.4, 59.2) | 53.0 (50.0, 57.0) | 0.043 |
BMI (kg/m2) | 24.4 (22.3, 26.5) | 24.0 (22.1, 26.3) | 0.150 |
Smoking history | 0.043 | ||
Nonsmoker | 343 (92.0%) | 603 (95.1%) | |
Current or Former smoker | 30 (8.0%) | 31 (4.9%) | |
Alcohol consumption | 0.072 | ||
Nondrinker | 368 (98.7%) | 611 (96.8%) | |
Current or Former drinker | 5 (1.3%) | 20 (3.2%) | |
Age at menarche (years) | < 0.001 | ||
< 13 | 28 (7.6%) | 101 (15.5%) | |
≥ 13 | 342 (92.4%) | 551 (84.5%) | |
Age at menopause (years) | < 0.001 | ||
Pre/Peri-menopausal | 187 (51.2%) | 184 (29.0%) | |
< 51 | 109 (29.9%) | 291 (46.0%) | |
≥ 51 | 69 (18.9%) | 158 (25.0%) | |
Parity | < 0.001 | ||
< 2 | 246 (66.1%) | 553 (85.3%) | |
≥ 2 | 126 (33.9%) | 95 (14.7%) | |
Breastfeeding duration (months) | < 0.001 | ||
< 13 | 139 (39.7%) | 422 (66.8%) | |
≥ 13 | 211 (60.3%) | 210 (33.2%) | |
Use of estrogen or estrogen replacement therapy | 0.598 | ||
No | 355 (95.9%) | 514 (96.6%) | |
Yes | 15 (4.1%) | 18 (3.4%) | |
Family history of breast cancer | 0.015 | ||
No | 349 (93.8%) | 615 (97.0%) | |
Yes | 23 (6.2%) | 19 (3.0%) | |
Education (years) | 0.200 | ||
< 13 | 284 (76.1%) | 518 (79.6%) | |
≥ 13 | 89 (23.9%) | 133 (20.4%) | |
Monthly household income per capita (RMB/month) | 0.062 | ||
< 1000 | 39 (11.2%) | 50 (7.7%) | |
1000–1999 | 114 (32.9%) | 187 (28.9%) | |
2000–2999 | 117 (33.7%) | 228 (35.3%) | |
≥ 3000 | 77 (22.2%) | 181 (28.0%) | |
Red meat consumption | 0.372 | ||
Rare | 174 (46.6%) | 324 (49.5%) | |
Occasional | 148 (39.7%) | 235 (35.9%) | |
Often | 51 (13.7%) | 95 (14.5%) | |
Pickled food consumption | < 0.001 | ||
Rare | 222 (59.5%) | 597 (91.8%) | |
Occasional | 98 (26.3%) | 41 (6.3%) | |
Often | 53 (14.2%) | 12 (1.8%) | |
Fried food consumption | 0.169 | ||
Rare | 309 (82.8%) | 564 (86.1%) | |
Occasional | 50 (13.4%) | 78 (11.9%) | |
Often | 14 (3.8%) | 13 (2.0%) | |
Smoked food consumption | 0.103 | ||
Rare | 352 (94.9%) | 610 (96.7%) | |
Occasional | 15 (4.0%) | 20 (3.2%) | |
Often | 4 (1.1%) | 1 (0.1%) | |
Barbequed food consumption | 0.001 | ||
Rare | 345 (92.5%) | 616 (97.5%) | |
Occasional | 21 (5.6%) | 14 (2.2%) | |
Often | 7 (1.9%) | 2 (0.3%) |