Association of sleep duration and depressive symptoms with mortality in cancer survivors

Background Evidence of the association between sleep duration, depressive symptoms, and mortality in cancer survivors is limited. Methods 2,111 participants from the National Health and Nutrition Examination Surveys were involved and linked to a mortality database up to 31 December 2019. Sleep duration was self-reported at baseline. Depressive symptom was assessed using the Patient Health Questionnaire (PHQ-9) and a total score of >= 10 is considered clinically relevant depressive symptoms. Cox proportional hazards regression model was the main statistical models. Results A 2% increase in all-cause mortality was found for each 1-point increase in depressive symptoms score (hazard ratio [HR], 1.02; 95% confidence interval [CI], 1.00-1.03). Compared with those patients who slept 7 h, positive associations of < 6 h (HR, 1.79; 95% CI, 1.29-2.50), 8 h (HR, 1.46; 95% CI, 1.15-1.85), and > 8 h (HR, 1.49; 95% CI, 1.09-2.05) durations with all-cause mortality were observed. In the joint analysis, cancer survivors with depressive symptoms had a higher risk of all-cause mortality when sleeping < 6 h (HR, 1.69; 95% CI, 1.09-2.62) or >= 8 h (HR, 1.55; 95% CI, 1.02-2.35). Limitations Dynamics of sleep and depression data were not available. Conclusions Long (>= 8 h) and short (< 6 h) sleep duration was both associated with increased risks of all-cause deaths after adjusting for depressive symptoms scores. We also observed a joint effect of sleep duration and depressive symptoms. The findings may provide evidence to guide optimal sleep duration for prolonged cancer survival.