Table 1. Characteristics of the study population and control group.
| Features | Breast cancer | Control |
|---|---|---|
| Women | 11 101 | 18 910 |
| Mean age (years) | 48.2±17.7 | 44.8 ± 9.7 |
| Ductal carcinoma in situ | 2 099 (18.9%) | - |
| Lobular carcinoma in situ | 423 (3.8%) | |
| Invasive ductal carcinoma | 6,859 (61.7%) | |
| Invasive lobular carcinoma | 865 (7.8%) | |
| Adenocystic carcinoma | 281 (2.5%) | |
| Metaplastic carcinoma | 133 (1.2%) | |
| Micropapillary carcinoma | 97 (0.9%) | |
| Mucinous carcinoma | 78 (0.7%) | |
| Papillary carcinoma | 76 (0.7%) | |
| Tubular carcinoma | 45 (0.4%) | |
| Mixed carcinoma | 87 (0.8%) | |
| Others | 58 (0.5%) | |
| Premenopausal BC | 2 150 (19.4%) | - |
| Postmenopausal BC | 8 951 (80.6%) | - |
| Family oncological history | 5 278 (47.5%) | 1 878 (9.9%) |
| Urban area (%) | 7 650 (68.9%) | 13 238 (70%) |
| Rural area (%) | 3 451 (31.2%) | 5 672 (30%) |
| Current or former smoker | 3 105 (30%) | 2 463 (13.0%) |
| Active symptoms of allergy when BC was confirmed | 2 056 (18.5%) | 5 201 (27.5%) |
| Allergy including symptoms in the past | 2 351 (21.2%) | 6 098 (32.2%) |
| Mean age at onset of allergy symptoms (years) | 11.2±7.8 | 9.1±5.6 |
| Mean time of allergy durations (years) | 18.6±17.5 | 20.1±11.8 |
| Atopic dermatitis | 431 (3.8%) | 767 (4.1%) |
| Allergic rhinitis | 1 990 (17.9%) | 3 740 (19.6%) |
| Bronchial asthma | 897 (8.1%) | 2 118 (11.2%) |
| Diabetes | 1 080 (9.7%) | 1 323 (7%) |
| Arterial hypertension | 2 045 (18.4%) | 2 201 (11.6%) |
| Overweight (BMI>25) | 2788 (25.1%) | 4 044 (21.4%) |
| Heart failure | 845 (7.6%) | 752 (4%) |
| COPD | 1 028 (9.3%) | 1 437 (5.6%) |
BMI—body mass index, COPD—chronic obstructive pulmonary disease