Association Between Sleep Continuity and Cognition in Breast Cancer Survivors: A Cross-Sectional Study.

BACKGROUND: Cancer-related cognitive dysfunction (CRCD) and insomnia are distressing for breast cancer survivors and commonly co-occur, yet little is known about how sleep patterns influence cognition. We aim to characterize these associations. METHODS: We analyzed baseline data from an RCT of breast cancer survivors with insomnia and CRCD who completed sleep tracking via the Consensus Sleep Diary (CSD) and/or a wearable smartwatch (WA). Sleep patterns included wake after sleep onset (WASO), number of awakenings (NWAK), time spent in bed (TIB), total sleep time (TST), and sleep efficiency (SE). Cognition was assessed by FACT-Cog PCI and HVLT-R. Univariable and multivariable linear regression examined associations between sleep patterns and cognition. RESULTS: Among 158 participants, the mean age [range] was 57 [28-83] and 21.5% were non-white. None of the sleep metrics collected from either the CSD or WA were significantly associated with subjective cognition. From CSD data, greater WASO was significantly associated with worse objective cognition (Coef. = -.08, p = .003, 95% CI [-0.1, -0.03]) and higher SE was significantly associated with better objective cognition (Coef. = .2, p = .011, 95% CI [0.05, 0.4]). From WA data, greater NWAK was significantly associated with worse objective cognition (Coef. = -.2, p = .010, 95% CI [-0.3, -0.04]). CONCLUSION: Sleep patterns were not significantly associated with subjective cognition, but sleep fragmentation, measured by both CSD and WA, was significantly associated with worse objective cognition. Interventions targeting sleep fragmentation may be used to promote objective cognition during breast cancer survivorship.Clinica Trials Registration: NCT04837820.