Mean self-reported average hours of sleep per night by patient characteristic.
All patients
Premenopausal
Postmenopausal
Hours of sleep per night, mean (SD)
Hours of sleep per night, mean (SD)
Hours of sleep per night, mean (SD)
All
7.03 (1.20)
N/A
N/A
7.08 (1.24)
N/A
N/A
7.02 (1.20)
N/A
N/A
Stage
0.031
0.36
0.40
0.60
0.026
0.26
0 (DCIS)
6.98 (1.20)
7.11 (0.85)
6.95 (1.28)
1
7.14 (1.20)
7.07 (1.42)
7.15 (1.16)
2
6.99 (1.16)
7.23 (1.28)
6.94 (1.13)
3
6.65 (1.14)
6.42 (1.17)
6.67 (1.14)
4
7.12 (1.68)
6.00 (1.41)
7.24 (1.69)
Grade
0.032
0.052
0.022
0.89
0.018
0.049
1
7.23 (1.20)
7.63 (1.34)
7.16 (1.17)
2
7.05 (1.24)
6.75 (1.27)
7.11 (1.23)
3
6.89 (1.18)
7.27 (1.38)
6.82 (1.13)
ER status
0.31
0.71
0.38
0.88
0.47
0.69
Positive
7.04 (1.21)
7.10 (1.30)
7.03 (1.19)
Negative
6.94 (1.19)
6.88 (0.98)
6.95 (1.23)
HER2 status
0.17
0.23
0.79
0.64
0.17
0.31
Positive
6.91 (1.10)
7.00 (0.89)
6.89 (1.13)
Negative
7.06 (1.21)
7.09 (1.43)
7.06 (1.18)
value of ANOVA (univariate); value of sleep duration in ordinal or standard logistic regression adjusted for age, race, hormone replacement therapy (HRT), family history of breast cancer, body mass index (BMI), current smoking, current alcohol consumption, and physical activity.