Longitudinal associations between mild behavioral impairment, sleep disturbance, and progression to dementia

Abstract

AbstractBackgroundClinical guidelines recommend incorporating non‐cognitive markers into dementia screening to improve detection. Two of these markers are mild behavioral impairment (MBI) and sleep. MBI is a neurobehavioral syndrome capturing later‐life emergent and persistent neuropsychiatric symptoms, which represent a change from longstanding behavior or personality, as a high‐risk group for incident cognitive decline and dementia. Sleep disturbances include difficulties initiating and maintaining sleep, are common in older adults and are associated with greater risk for dementia. We investigated the longitudinal associations between MBI and sleep disturbance and their association with incident dementia.MethodsData were obtained from the National Alzheimer’s Coordinating Center. MBI was derived from Neuropsychiatric Inventory Questionnaire (NPI‐Q) based on a published algorithm. The presence of sleep disturbance was obtained from the NPI‐Q nighttime behaviors item. Cox proportional hazard regressions, adjusted for age, sex, education, and cognitive diagnosis, were used to determine the associations between 1) baseline MBI and incident sleep disturbance (n = 8348); 2) baseline sleep disturbance and incident MBI (n = 9679) and 3) baseline sleep disturbance, with and without concurrent MBI, and incident dementia (n = 12296).ResultsDemographics are summarized in Table 1. As per Table 2, the rate of developing sleep disturbance was 3.3‐fold higher in older adults with MBI at baseline compared to those without MBI (95%CI: 2.96‐3.67; p<0.001). Likewise, the rate of developing MBI was 2.1‐fold higher in older adults with baseline sleep disturbance compared to those without sleep disturbance (95%CI: 1.84‐2.36, p<0.001). The incidence rate of dementia was 2.23‐fold greater in older adults with both MBI and sleep disturbance, relative to sleep disturbance alone (95%CI: 1.65‐3.00; p<0.001).ConclusionsIn this group of dementia‐free older adults, we found a bidirectional relationship between MBI and sleep disturbance. Sleep disturbance was more strongly associated with incident dementia when co‐morbid with MBI. This relationship might suggest a common etiology for MBI and SD, as both were linked with incident dementia. Thus, including both sleep disturbance and MBI into modeling may improve dementia prognostication. Future studies should incorporate biomarkers and additional clinical markers for Alzheimer’s disease and other neurodegenerative disease into the modeling to better understand these relationships.