Sleep Disturbance and Cognitive Trajectories Among Older Adults with Subjective Cognitive Decline: The Roles of Age and Sleep Treatment.

STUDY OBJECTIVES: Growing evidence indicates that subjective cognitive decline (SCD), characterized by self-reported cognitive deterioration without measurable cognitive impairment, may be an early indicator of Alzheimer's Disease. This study investigated the association between baseline sleep disturbance and a 10-year trajectory of global cognitive performance in adults with SCD and examined if this association was moderated by age (50-64 years and ≥65 years) and sleep treatment.

METHODS: Using six waves (2010-2020) of the Health and Retirement Study, we included individuals aged ≥50 years who reported SCD but had no objective cognitive impairment at baseline (2010) and had final wave of cognitive data (n=1,372). Latent growth curve modeling was employed to examine the associations between self-reported sleep disturbance and cognitive trajectories from 2010 to 2020, controlling for sociodemographic and health-related factors.

RESULTS: In the full sample, baseline sleep disturbance was not significantly associated with cognitive change. However, a significant interaction between sleep disturbance and age group was found (β=-0.04, 95% CI [-0.08, -0.003]). Stratified analyses showed that poorer sleep was associated with faster cognitive decline in those aged ≥65 years (β=-0.04, 95% CI [-0.07, -0.005]; n=558), and receiving sleep treatment was associated with a reduced impact of sleep disturbance on cognitive decline (β=0.31, 95% CI [0.02, 0.60]). These associations were not significant in those aged 50-64 years (n=814).

CONCLUSIONS: Sleep disturbance was an independent risk factor of future cognitive decline in older adults ≥65 years with SCD. Sleep treatment may mitigate this decline, offering a potential intervention strategy.