Table 1 Characteristics of the study population
From: Smoking and high-risk mammographic parenchymal patterns: a case-control study
| Â | Cases | Controls |
|---|---|---|
| Â | (P2+DY; | (N1+P1; |
Characteristics | n = 203) | n = 203) |
Mean age (years) | 59.3 | 59.3 |
Mean body mass index | 25.2 | 27.4 |
Mean waist:hip ratio | 2.1 | 2.4 |
Menopausal status (n) | Â | Â |
    Premenopausal | 44 | 24 |
    Postmenopausal | 148 | 165 |
    Unknown | 11 | 14 |
    Mean age at menarche (years) | 13.0 | 12.7 |
    Mean age at menopause (years) | 47.7 | 47.0 |
Number of children (n) | Â | Â |
    0 | 31 | 16 |
    1 | 27 | 26 |
    2 | 96 | 82 |
    3 | 34 | 47 |
    4+ | 15 | 29 |
   Unknown | - | 3 |
History of benign breast diseases (n) | Â | Â |
    No | 188 | 198 |
    Yes | 15 | 5 |
Hysterectomy (n) | Â | Â |
    No | 141 | 152 |
    Yes | 60 | 49 |
    Unknown | 2 | 2 |
HRT use (n) | Â | Â |
    Never | 106 | 131 |
    Past | 22 | 25 |
    Current | 73 | 43 |
    Unknown | 2 | 4 |
Smoking (n) | Â | Â |
    Never | 121 | 120 |
    Past | 62 | 53 |
    Current | 20 | 30 |