OBJECTIVES

This study aimed to identify the effect of sleep traits on the risk of breast cancer incidence and adverse progression and mortality.

METHODS

Cohort studies measuring the relationship between sleep traits (including sleep quality and sleep duration) and breast cancer risk were eligible for inclusion. We searched the Web of Science, PubMed, EMBASE and Cochrane library databases for studies published between 2014 and 2024. Maximum covariate-adjusted odds ratio (OR) was combined. A fixed or a randomized effect model was applied according to the heterogeneity.

RESULTS

34 studies met the inclusion and exclusion criteria. Low quality sleep significantly increased the risk of incidence (OR:1.09, 95%CI:1.05-1.13), adverse progression (OR:1.55,95%CI:1.51-1.59), and specific mortality (OR:1.54, 95%CI:1.50-1.58) of breast cancer. Sleep duration >9 h had a poor effect on breast cancer-specific mortality (OR:1.45,95%CI:1.02-2.04).

CONCLUSIONS

The available evidence points to sleep traits as primarily influencing progression in breast cancer patients and having a relatively small effect on breast cancer incidence. Prolonged sleep may lead to breast cancer-specific mortality, but more research is needed in the future to continue to explore the impact of sleep duration and breast cancer risk.