Sleep Duration and Cognitive Function: The Akershus Cardiac Examination 1950 Study

Abstract

Introduction: Sleep duration is proposed as a lifestyle-related risk factor for cognitive impairment. We investigated the association between sleep duration and cognitive function in a large population-based cohort aged 62-65 years.

Methods: Cross-sectional analyses from the Akershus Cardiac Examination 1950 Study. Linear and nonlinear models were conducted to explore the association between self-reported sleep duration and cognitive function, adjusted for established risk factors for cognitive impairment.

Results: We included 3,348 participants, mean age (SD) was 63.9 ± 0.6 years, 48.2% were women, and 47.9% had education >12 years. Mean sleep duration (SD) was 7.0 ± 1.0 h, and 10.2% had abnormal sleep duration (<6 or >8 h). Individuals reporting <6 h or >8 h of sleep scored significantly lower on MoCA test and delayed recall trial in adjusted analysis.

Conclusions: Sleep duration showed an inverted U-shaped association with global cognitive function and memory, suggesting that both shortened and prolonged sleep are related to adverse brain health.

Trial registration: ClinicalTrials.gov NCT01555411.

Keywords: Aging and cognition; Cognitive function; Risk factors; Sleep duration.