Table 1:
Descriptive Statistics of the Study Population
| Variable | Cases (%) | Controls (%) | |
|---|---|---|---|
| Age | |||
| Mean, Standard deviation (SD) | 56.82, SD=10.29 | 56.39, SD=9.90 | |
| Education | |||
| High School or less | 389 (34.5) | 300 (25.7) | |
| College/Trade certificate | 339 (30.0) | 347 (29.7) | |
| University degree | 271 (24.0) | 299 (25.6) | |
| Graduate or professional school degree | 130 (11.5) | 223 (19.1) | |
| Household income | |||
| Less than $15,000 | 70 (6.2) | 32 (2.7) | |
| $15,000 to $29,999 | 140 (12.4) | 89 (7.6) | |
| $30,000 to $59,999 | 281 (24.9) | 268 (22.9) | |
| $60,000 to $79,999 | 139 (12.3) | 158 (13.5) | |
| $80,000 or more | 350 (31.0) | 463 (39.6) | ptrend < 0.01 |
| Not stated | 150 (13.3) | 159 (13.6) | |
| Ethnicity₸ | |||
| European | 703 (62.2) | 912 (78.0) | |
| Chinese | 239 (21.2) | 115 (9.8) | |
| South Asian | 32 (2.8) | 34 (2.9) | |
| Filipino | 60 (5.3) | 38 (3.3) | |
| Japanese | 24 (2.1) | 14 (1.2) | |
| Other | 50 (4.4) | 42 (3.6) | |
| Mixed | 22 (1.9) | 14 (1.2) | p < 0.01 |
| BMI | |||
| Mean, SD | 25.61, SD=5.27 | 25.15, SD=5.00 | p = 0.05 |
| Underweight (< 18.5) | 27 (2.4) | 27 (2.3) | |
| Normal (18.5 – 25) | 585 (52.1) | 665 (57.3) | |
| Overweight (25 – 30) | 336 (29.9) | 309 (26.6) | |
| Obese (30+) | 174 (15.5) | 159 (13.7) | ptrend = 0.03 |
| Reproductive History | |||
| Menopausal status | |||
| Premenopausal | 434 (38.4) | 474 (40.5) | |
| Postmenopausal | 695 (61.6) | 695 (59.5) | p = 0.30 |
| Ever Pregnant | |||
| Never | 191 (16.9) | 240 (20.5) | |
| Ever | 937 (83.1) | 928 (79.5) | p = 0.03 |
| Lifestyle | |||
| Age at first mammogram | |||
| Years: Mean, SD | 44.69, SD=8.99 | 42.72, SD=7.70 | p < 0.01 |
| Family History of Breast Cancer | |||
| Never | 906 (80.2) | 1002 (85.7) | |
| Ever | 224 (19.8) | 167 (14.3) | p < 0.01 |
| Smoking | |||
| Current Smoker | |||
| No | 1057 (93.7) | 1096 (93.8) | |
| Yes | 71 (6.3) | 72 (6.2) | p = 0.90 |
| Pack-years | |||
| Years: Mean, SD | 5.63, SD=11.97 | 5.33, SD=11.33 | p = 0.72 |