Table 1. Baseline characteristics of breast cancer survivors in the Women's Healthy Eating and Living Study across sleep duration categories.
| All N = 3047 | Sleep duration/night | P value | |||
|---|---|---|---|---|---|
|
| |||||
| Short, ≤6 h N = 931 | Middle, 7–8 h N = 1935 | Long, ≥9 h N = 181 | |||
| Age (years) mean(SD) | 52.8 (9.0) | 52.7 (8.6) | 52.9 (9.1) | 51.9 (9.3) | 0.30 |
| Race/ethnicity n (row %) | <.0001 | ||||
| White, non-Hispanic | 2597 | 725 (27.9) | 1716 (66.1) | 156 (6.0) | |
| Non-white | 450 | 206 (45.8) | 219 (48.7) | 25 (5.6) | |
| College educated n (row %) | 0.01 | ||||
| Yes | 1651 | 465 (28.2) | 1090 (66.0) | 96 (5.8) | |
| No | 1396 | 466 (33.4) | 845 (60.5) | 85 (6.1) | |
| Cancer stage at diagnosis n (row %) | 0.35 | ||||
| I | 1180 | 357 (30.3) | 754 (63.9) | 69 (5.8) | |
| II | 1386 | 432 (31.2) | 880 (63.5) | 74 (5.3) | |
| IIIA | 481 | 142 (29.5) | 301 (62.6) | 38 (7.9) | |
| Grade n (%) | 0.20 | ||||
| Well differentiated | 479 | 137 (28.6) | 321 (67.0) | 21 (4.4) | |
| Moderately differentiated | 1226 | 391 (31.9) | 763 (62.2) | 72 (5.9) | |
| Poorly differentiated | 1088 | 328 (30.1) | 683 (62.8) | 77 (7.1) | |
| Unspecified | 254 | 75 (29.5) | 168 (66.1) | 11 (4.3) | |
| Radiotherapya n (row %) | 0.36 | ||||
| Yes | 1870 | 554 (29.6) | 1204 (64.4) | 112 (6.0) | |
| No | 1173 | 376 (32.1) | 728 (62.1) | 69 (5.9) | |
| Chemotherapya n (row %) | 0.14 | ||||
| Yes | 2125 | 663 (31.2) | 1328 (62.5) | 134 (6.3) | |
| No | 920 | 266 (28.9) | 607 (66.0) | 47 (5.1) | |
| Menopausal statusa n (row %) | 0.09 | ||||
| Premenopausal | 341 | 85 (24.9) | 234 (68.6) | 22 (6.5) | |
| Postmenopausal | 2420 | 764 (31.6) | 1519 (62.8) | 137 (5.7) | |
| Perimenopausal | 281 | 79 (28.1) | 180 (64.1) | 22 (7.8) | |
| Insomnia rating scalea,b median (IQR) | 7.0 (7.0) | 10.0 (8.0) | 6.0 (6.0) | 6.0 (5.0) | <.001 |
| Number of Co-morbiditiesa,c n (row %) | 0.004 | ||||
| 0 | 1396 | 391 (28.0) | 922 (66.0) | 83 (5.9) | |
| 1 | 698 | 217 (31.1) | 445 (63.8) | 36 (5.2) | |
| 2 | 324 | 127 (39.2) | 174 (53.7) | 23 (7.1) | |
| 3 or more | 123 | 42 (34.1) | 74 (60.2) | 7 (5.7) | |
| Physical activity (met-min/wk) median (IQR) | 630.0 (1065. | 0) 525.0 (1020.0) | 675.0 (1110.0) | 555.0 (1000.0) | <.001 |
| BMI (kg/m2) mean(SD) | 27.3 (6.1) | 28.3 (6.7) | 26.8 (5.7) | 27.4 (5.8) | <.001 |
SD standard deviation, BMI body mass index
a
Missing chemotherapy data for 2 participants, menopausal status data for n = 5 participants, radiotherapy data for n = 4 participants, insomnia data for n = 5 participants, and co-morbidity data for n = 506 participants
b
Insomnia rating scale range: 0–20, scores ≥9 indicate insomnia
c
Co-morbidities were self-reported and included arthritis, osteoporosis, cardiovascular conditions, digestive conditions, diabetes, and miscellaneous conditions