Table 1 Characteristics of the Study Population*
From: Breast density and polymorphisms in genes coding for CYP1A2 and COMT: the Multiethnic Cohort
Characteristic | Cases | Controls | All |
|---|---|---|---|
Number of women | 325 | 250 | 575 |
Ethnicity | |||
Caucasian | 112 (34.5) | 74 (29.6) | 186 (32.4) |
Japanese | 168 (51.7) | 101 (40.4) | 269 (46.8) |
Native Hawaiian | 43 (13.2) | 75 (30.0) | 118 (20.5) |
Number of mammograms | 3.4 ± 1.9 | 2.5 ± 1.2 | 3.0 ± 1.7 |
Age at first mammogram (years) | 57.4 ± 8.9 | 56.8 ± 9.9 | 57.1 ± 9.3 |
Percent density at first mammogram (%) | 36.7 ± 22.8 | 30.6 ± 23.3 | 34.0 ± 23.2 |
Time between first and last mammogram (years) | 5.2 ± 3.8 | 4.2 ± 3.8 | 4.7 ± 3.8 |
Postmenopausal at time of first mammogram | 233 (71.7) | 153 (61.2) | 386 (67.1) |
Hormone replacement therapy by mammogram | |||
None | 472 (42.5) | 290 (47.2) | 762 (44.3) |
Estrogen only | 282 (25.5) | 207 (33.7) | 489 (28.4) |
Estrogen plus progestin | 354 (32.0) | 117 (19.1) | 471 (27.3) |
Overweight/obese (BMI ≥ 25 kg/m2) | 121 (37.2) | 113 (45.2) | 234 (40.7) |
Family history of breast cancer | 56 (17.2) | 31 (12.4) | 87 (15.1) |
Age at menarche younger than 13 years | 194 (59.7) | 136 (54.4) | 330 (57.4) |
Age at first live birth older than 30 years | 29 (8.9) | 26 (10.4) | 55 (9.6) |
Nulliparity | 43 (13.2) | 31 (12.4) | 74 (12.9) |
Parity 3+ children | 72 (22.2) | 53 (21.2) | 125 (21.7) |