Associations between sleep duration patterns and cognitive decline trajectories in older Chinese adults

Abnormal sleep duration has been identified as a risk factor for cognitive decline. However, most studies have measured sleep duration and cognitive function at a single time point, while both tend to decrease with age. This study aimed to investigate the association between changes in sleep duration patterns and cognitive trajectories in older adults. Using longitudinal data (2005–2014) from the Chinese Longitudinal Healthy Longevity Survey, a total of 4347 subjects were included in this study. Cognitive function was measured with the Chinese version of the Mini-Mental State Examination. Group-based trajectory models were used to identify the trajectories of sleep duration and cognitive decline within the study sample as the participants aged. Furthermore, the association between sleep duration patterns and cognitive trajectories was examined by multinomial logistic regression analysis. Using the medium-stable sleep duration pattern as a reference, the trajectory with a long and increased sleep duration pattern was more likely to be associated with the slight cognitive decline trajectory (OR = 1.80; 95% CI 1.31–2.44). Persistent short sleep was associated with a decreased likelihood of having a rapid cognitive decline trajectory (OR = 0.32; 95% CI 0.12–0.75). Changes in sleep duration over time were independently associated with cognitive decline and may be a marker of cognitive decline. Tracking of sleep duration over time in older adults may provide a useful insight for prevention of cognitive decline, and the increased sleep duration should be noticed with greater vigilance.