Table 1.
Descriptive characteristics of study group at enrollment, n = 1257
| Characteristic | Case subjects n = 419 | Control subjects n = 838 | P * |
|---|---|---|---|
| Age, mean (SD), y | 62.56 (6.93) | 62.46 (6.86) | .82 |
| Race/region, No. (%) | .17 | ||
| White/Northeast | 149 (35.6) | 318 (37.9) | |
| White/South | 77 (18.4) | 138 (16.5) | |
| White/West | 117 (27.9) | 246 (29.4) | |
| Non-white/Northeast | 10 (2.4) | 18 (2.1) | |
| Non-white/South | 45 (10.7) | 59 (7.0) | |
| Non-white/West | 21 (5.0) | 59 (7.0) | |
| Education level; No. (%) | .65 | ||
| Less than high school degree | 111 (26.7) | 234 (28.0) | |
| Post-high school/some college | 148 (35.6) | 308 (36.9) | |
| College degree or higher | 157 (37.7) | 293 (35.1) | |
| Neighborhood SES index, mean (SD) | 72.31 (9.47) | 73.48 (8.33) | .03 |
| Body mass index, mean (SD), kg/m2 | 29.03 (5.94) | 27.65 (5.60) | <.001 |
| Body mass index category, No. (%) | <.001 | ||
| Underweight/normal, <25 kg/m2 | 120 (28.8) | 299 (35.9) | |
| Overweight, 25–<30 kg/m2 | 144 (34.5) | 305 (36.7) | |
| Obese, ≥30 kg/m2 | 153 (36.7) | 228 (27.4) | |
| Alcohol intake, No. (%) | .29 | ||
| 0 drinks/wk | 137 (32.9) | 275 (33.1) | |
| <1 drink/wk | 136 (32.7) | 295 (35.5) | |
| 1–6 drinks/wk | 95 (22.8) | 193 (23.2) | |
| ≥7 drinks/wk | 48 (11.5) | 69 (8.3) | |
| Smoking status, No. (%) | <.001 | ||
| Never smoked | 209 (50.1) | 489 (59.6) | |
| Past smoker | 173 (41.5) | 288 (35.1) | |
| Current smoker | 35 (8.4) | 43 (5.2) | |
| Total physical activity, MET-h/wk, mean (SD) | 10.25 (12.04) | 12.89 (15.42) | <.001 |
| Healthy Eating Index score, mean (SD) | 66.03 (11.40) | 67.13 (10.65) | .09 |
| Gail risk score, mean (SD) | 1.83 (1.12) | 1.65 (0.89) | <.001 |
| Any postmenopausal hormone therapy use, No. (%) | .40 | ||
| Never use | 197 (47.1) | 387 (46.2) | |
| Past user | 54 (12.9) | 132 (15.8) | |
| Current user | 167 (40.0) | 318 (38.0) | |
| OS participation, No. (%) | 221 (52.7) | 441 (52.6) | .97 |
| Hormone therapy trial assignment, No. (%) | .24 | ||
| Not randomly assigned | 349 (83.3) | 683 (81.5) | |
| E-alone intervention | 13 (3.1) | 31 (3.7) | |
| E-alone control | 17 (4.1) | 41 (4.9) | |
| E + P intervention | 28 (6.7) | 41 (4.9) | |
| E + P control | 12 (2.9) | 42 (5.0) | |
| Dietary modification trial assignment, No. (%) | .74 | ||
| Not randomly assigned | 275 (65.6) | 547 (65.3) | |
| Intervention | 51 (12.2) | 114 (13.6) | |
| Control | 93 (22.2) | 177 (21.1) | |
| Calcium and vitamin D trial assignment, No. (%) | .19 | ||
| Not randomly assigned | 326 (77.8) | 613 (73.2) | |
| Intervention | 49 (11.7) | 123 (14.7) | |
| Control | 44 (10.5) | 102 (12.2) | |
| ER/PR status, No. (%) | – | ||
| ER+/PR+ | 288 (74.0) | – | |
| ER+/PR- | 40 (10.3) | – | |
| ER-/PR- | 61 (15.7) | – |
*
P values calculated from χ2 tests or t tests for categorical and continuous variables, respectively. All tests were two-sided. E = estrogen; ER = estrogen receptor; MET = metabolic equivalent task; OS = observational study; P = progestin; PR = progesterone receptor; SES = socioeconomic status.