Sleep Quality and Duration and the Risk of Breast Cancer in a Population-Based Study

摘要

Background: The association between sleep and breast cancer is uncertain. This study was to prospectively investigate the joint effects of the quality and duration of sleep on the development of breast cancer. Methods: 90,881 women aged more than 20 years were selected from a prospective cohort in Taiwan. Self-administered questionnaires were used to collected information on duration and quality of sleep as well as potential confounders. Incident cases of breast cancer were self-reported in subsequent medical examinations. Sleep score was constructed to reflect the participants' sleep profiles with regard to both duration and quality via additive model. The proportional Cox regression method was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Results: 292 individuals reported incident cases of breast cancer at follow-up. The sleep score was associated with the risk of breast cancer with exposure-response trend (p < 0.001). Every five-unit increment of sleep score was associated with an 8% decreased risk of breast cancer after adjusting for potential confounders. Higher risk of breast cancer were observed in participants in the lowest quartile (HR: 1.52; 95% CI: 1.07-2.14) and second lowest quartile (HR: 1.45; 95% CI: 1.05-2.02) of sleep scores compared with those in the highest quartile. Conclusion: A poor sleep profile is associated with an increased risk of breast cancer. Our findings suggest that improving sleep behavior by considering both duration and quality can be an important approach in the prevention of breast cancer.