Table 2. Association between post-diagnosis sleep duration and mortality (N=3682).

	Model 1		Model 2		Model 3
Hours of sleep per night (deaths/N)	HR	(95% CI)	HR	(95% CI)	HR	(95% CI)
All-cause deaths (976 deaths)
⩽6 h (257/965)	1.03	(0.87–1.22)	1.01	(0.86–1.20)	1.05	(0.88–1.24)
7 h (315/1234)	0.97	(0.82–1.14)	0.96	(0.82–1.13)	1.00	(0.85–1.18)
8 h (292/1100)	1 (reference)
⩾9 h (112/383)	1.45	(1.16–1.80)	1.40	(1.12–1.74)	1.37	(1.10–1.71)
P-value for non-linear trend	0.0008		0.009		0.02
Breast cancer deaths (412 deaths)
⩽6 h (100/965)	1.07	(0.82–1.40)	1.10	(0.84–1.44)	1.13	(0.86–1.48)
7 h (143/1234)	1.09	(0.86–1.39)	1.07	(0.84–1.36)	1.10	(0.86–1.40)
8 h (124/1100)	1 (reference)
⩾9 h (45/383)	1.49	(1.05–2.10)	1.46	(1.03–2.07)	1.46	(1.02–2.07)
P-value for non-linear trend	0.13		0.11		0.12
Non-breast cancer deaths (564 deaths)
⩽6 h (157/965)	1.03	(0.83–1.28)	0.98	(0.79–1.23)	1.01	(0.81–1.27)
7 h (172/1234)	0.90	(0.73–1.11)	0.89	(0.72–1.10)	0.90	(0.73–1.12)
8 h (168/1100)	1 (reference)
⩾9 h (67/383)	1.40	(1.05–1.87)	1.37	(1.03–1.83)	1.34	(1.01–1.79)
P-value for non-linear trend	0.003		0.02		0.03

Abbreviations: BMI=body mass index; CI=confidence intervals; HR=hazard ratio; OC=oral contraceptive; PMH=postmenopausal hormone.

Model 1: year of diagnosis, age at diagnosis, time since diagnosis, cancer stage, surgery, chemotherapy, radiation therapy, hormone therapy, prevalent diabetes or heart disease, missing indicators for oncologic treatments.

Model 2: Model 1+age, marital status, education level, income, OC use, number of pregnancies, family history of breast cancer, menopausal status, PMH use.

Model 3: Model 2+BMI, alcohol consumption, smoking, caffeine, calories intake, physical activity.

Sample includes women who received a breast cancer diagnosis and completed either the 1986, 2000, 2002, or 2008 sleep duration assessment ⩽4 years after. Bold characters indicate statistically significant results. Italic characters indicate the reference group.