Table 4 Association between post-diagnosis difficulties initiating or maintaining sleep and mortality (N=1353)

From: Sleep and survival among women with breast cancer: 30 years of follow-up within the Nurses’ Health Study

 

Model 1

Model 2

Model 3

Sleep difficulties (deaths/N)

HR

(95% CI)

HR

(95% CI)

HR

(95% CI)

All-cause deaths (366 deaths)

      

Rarely/never (210/803)

1 (reference)

Occasionally (123/442)

1.07

(0.85–1.33)

1.04

(0.83–1.30)

1.05

(0.84–1.32)

Regularly (33/108)

1.40

(0.96–2.04)

1.48

(1.01–2.16)

1.49

(1.02–2.19)

P-value for non-linear trend

0.58

0.24

0.25

Breast cancer deaths (119 deaths)

      

Rarely/never (65/803)

1 (reference)

Occasionally (41/442)

1.08

(0.73–1.61)

1.09

(0.73–1.62)

1.09

(0.72–1.63)

Regularly (13/108)

1.55

(0.84–2.86)

1.62

(0.87–3.03)

1.78

(0.94–3.36)

P-value for non-linear trend

0.57

0.48

0.37

Non-breast cancer deaths (247 deaths)

      

Rarely/never (145/803)

1 (reference)

Occasionally (82/442)

1.04

(0.79–1.37)

1.00

(0.76–1.32)

1.00

(0.76–1.32)

Regularly (20/108)

1.37

(0.85–2.21)

1.41

(0.87–2.28)

1.38

(0.85–2.26)

P-value for non-linear trend

0.65

0.30

0.32

  1. Abbreviations: BMI=body mass index; CI=confidence intervals; HR=hazard ratio; OC=oral contraceptive; PMH=postmenopausal hormone.
  2. 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.
  3. Model 2: Model 1+age, marital status, education level, income, OC use, number of pregnancies, family history of breast cancer, menopausal status, PMH use.
  4. Model 3: Model 2+BMI, alcohol consumption, smoking, caffeine, calories intake, physical activity.
  5. Sample includes women who completed the 2000 sleep difficulties assessment (only available at this time point) and who were diagnosed with breast cancer ⩽4 years before (i.e., between 1996 and 2000). Bold characters indicate statistically significant results. Italic characters indicate the reference group.
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