Table 3. Multivariable-adjusted associations of time-varying sleep duration change categories with breast cancer recurrence, mortality, and all-cause mortality among 3047 breast cancer survivors in the Women's Healthy Eating and Living Study.
| Na | N observationsb | Breast cancer recurrence (n = 568 events) HR (95% CI) | Breast cancer mortality (n = 446 events) HR (95% CI) | All-cause mortality (n = 649 events) HR (95% CI) | |
|---|---|---|---|---|---|
| Sleep category | |||||
| Consistent short sleep (≤6 h/night) | 553 | 2073 | 0.93 (0.74, 1.17) | 0.78 (0.60, 1.01) | 0.91 (0.73, 1.12) |
| Consistent middle sleep (7–8 h/night) | 1282 | 4839 | 1 (ref) | 1 (ref) | 1 (ref) |
| Consistent long sleep (≥9 h/night) | 67 | 301 | 1.30 (0.85, 1.98) | 1.22 (0.75, 1.99) | 1.46 (0.97, 2.21) |
| Inconsistently short sleepc | 864 | 1820 | 0.82 (0.64, 1.06) | 0.80 (0.61, 1.06) | 0.79 (0.63, 0.98) |
| Inconsistently long sleepd | 281 | 585 | 1.60 (1.18, 2.18) | 1.70 (1.23, 2.36) | 1.47 (1.12, 1.93) |
Bold values indicate statistically significant associations
Models also controlled for age, stage, grade, time-varying body mass index (kg/m2) and number of co-morbidities, race/ethnicity, intervention group, study site, and number of sleep assessments
CI confidence interval, HR Hazard ratio
a
Total number of women in each sleep duration change category at the last observation
b
Total number of sleep records (across all time points) available per sleep duration change category
c
Inconsistently short sleep: reflects transitions from middle to short sleep duration (or vice versa) over time
d
Inconsistently long sleep: reflects transitions from middle to long sleep duration (or vice versa) over time