Table 1 Characteristics of the case and control samples
Cases (n = 213) mean (SD) | Controls (n = 630) mean (SD) | P a | |
|---|---|---|---|
Age at mammogram (years) | 51.6 (7.6) | 51.5 (7.4) | 0.9 |
Body mass index (kg/m2) | 22.5 (2.7) | 22.6 (2.8) | 0.8 |
Age at menarche (years) | 14.6 (1.6) | 14.6 (1.6) | 0.9 |
Number of live birth (per child) | 2.11 (0.75) | 2.27 (0.91) | 0.02 |
Menopausal status (n, %) | 0.9 | ||
Premenopausal | 134 (62.9) | 395 (62.7) | |
Postmenopausal | 79 (37.1) | 235 (37.3) | |
Benign breast lump (n, %) | <0.0001 | ||
Yes | 34 (16.0) | 36 (5.6) | |
No | 179 (84.0) | 594 (94.4) | |
Ever smoking (n, %) | 0.08 | ||
Yes | 17 (8.0) | 30 (4.8) | |
Never | 196 (92.0) | 600 (95.2) | |
Ever alcohol consumption (n, %) | 0.04 | ||
Yes | 95 (44.6) | 232 (36.8) | |
Never | 118 (55.4) | 398 (63.2) | |
Physical exercise (n, %) | 0.2 | ||
More and equal 90 mins per week | 85 (39.9) | 223 (35.4) | |
Less than 90 mins per week | 128 (60.1) | 407 (64.6) | |
Ever use of hormonal therapy (n, %) | 0.3 | ||
Yes | 33 (15.5) | 82 (13.0) | |
Never | 180 (84.5) | 548 (87.0) | |
Mammographic measurements | |||
Cumulus | |||
Dense area (cm2) | 18.1 (14.9) | 15.6 (11.7) | 0.01 |
Non-dense area (cm2) | 84.3 (36.0) | 85.3 (34.2) | 0.7 |
Percentage dense area | 18.6 (12.3) | 16.2 (10.3) | 0.006 |
Total area (cm2) | 102.3 (37.3) | 100.9 (35.0) | 0.6 |
Density thresholds (0 to 4095) | 2174 (355) | 2142 (343) | 0.2 |
Altocumulus | |||
Dense area (cm2) | 14.3 (11.6) | 11.4 (8.4) | 0.0002 |
Non-dense area (cm2) | 85.0 (35.3) | 87.5 (34.7) | 0.4 |
Percentage dense area | 15.3 (10.8) | 12.4 (8.5) | 0.0001 |
Total area (cm2) | 99.2 (36.2) | 99.0 (34.8) | 0.9 |
Density thresholds (0 to 4095) | 2247 (301) | 2252 (300) | 0.8 |
Cirrocumulus | |||
Dense area (cm2) | 3.5 (3.4) | 3.0 (2.3) | 0.03 |
Non-dense area (cm2) | 98.1 (41.0) | 97.7 (38.8) | 0.9 |
Percentage dense area | 3.8 (2.8) | 3.3 (2.4) | 0.03 |
Total area (cm2) | 101.6 (41.4) | 100.8 (39.0) | 0.8 |
Density thresholds (0 to 4095) | 2559 (205) | 2574 (226) | 0.4 |