Research Article
A Matched Case-Control Study of Risk Factors for Breast Cancer Risk in Vietnam
Table 2
Characteristics of breast cancer cases and matched controls.
| | Risk factors | Characteristics | Cases () | Controls () | |
| | Reproductive factors | Age at menarche (years) | 15.8 | 16 | 0.2 | | Parity | | | | | 0 | 14 (4.9%) | 5 (1.7%) | | | 1 | 29 (9.8%) | 17 (5.8%) | | | 2 | 150 (51.0%) | 123 (41.8%) | | | 3 | 62 (21.1%) | 98 (33.3%) | | | 4+ | 30 (10.2%) | 49 (16.7%) | | | Mean parity | 2.3 | 2.6 | <0.0001 | | Age at first parity (years) | 24.5 | 23.8 | 0.05 | | Total months breastfeeding | 35.7 | 37.6 | 0.38 |
| | Anthropometric factors | Height | 154.8 | 155.4 | 0.1 | | Weight at age 18 (kg) | 47.2 | 46.2 | 0.03 | | BMI at age 18 | 19.7 | 19.1 | 0.002 | | BMI gain since age 18 | 1.72 | 1.66 | 0.82 | | BMI at diagnosis/ | 21.4 | 20.8 | 0.002 | | BMI at age 18 | | | | | <18 kg/m2 | 65 (22.2%) | 75 (26.2%) | | | 18–20 kg/m2 | 98 (33.6%) | 124 (43.4%) | | | >20 kg/m2 | 130 (44.4%) | 87 (30.4%) | |
| | Hormonal factors | Oral contraceptive use | | | | | No | 266 (91.4%) | 278 (95.5%) | | | Yes | 25 (8.6%) | 13 (4.5%) | 0.04 | | Menopause | | | | | No | 196 (74.5%) | 218 (76.2%) | | | Yes | 67 (25.5%) | 68 (23.8%) | 0.64 |
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cases refers to BMI at diagnosis of breast cancer, prior to treatment. For controls, it refers to BMI at time of interview.
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