Research Article
A Matched Case-Control Study of Risk Factors for Breast Cancer Risk in Vietnam
Table 4
Characteristics of breast cancer cases and matched controls for premenopausal women.
| | Risk factors | Characteristics | Cases () | Controls () | |
| | Reproductive factor | Age at menarche (years) | 15.8 | 15.7 | 0.64 | | Parity | | | | | 0 | 10 (5.3%) | 4 (2.1%) | | | 1 | 16 (8.2%) | 7 (3.6%) | | | 2 | 110 (56.1%) | 96 (49.0%) | | | 3 | 39 (19.9%) | 64 (32.7%) | | | 4+ | 14 (7.1%) | 24 (12.2%) | | | Mean parity | 2.2 | 2.5 | 0.0002 | | Age at first parity (years) | 24.2 | 23.7 | 0.25 | | Total months breastfeeding | 36.1 | 37.4 | 0.65 |
| | Anthropometric factors | Height | 155.1 | 155.9 | 0.1 | | Weight at age 18 (kg) | 47.4 | 45.8 | 0.002 | | BMI at age 18 | 19.7 | 18.8 | 0.0001 | | BMI gain since age 18 | 1.69 | 1.84 | 0.60 | | BMI at diagnosis/ | 21.44 | 21.68 | 0.002 | | BMI at age 18 | | | | | <18 kg/m2 | 42 (21.4%) | 60 (30.6%) | | | 18–20 kg/m2 | 64 (32.7%) | 80 (40.8%) | | | >20 kg/m2 | 89 (45.4%) | 50 (25.5%) | |
| | Hormonal factors | Oral contraceptive use | | | | | No | 173 (89.2%) | 184 (94.9%) | | | Yes | 21 (10.8%) | 10 (5.2%) | 0.04 |
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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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