Sleep and Tau Pathology in Vietnam War Veterans with Preclinical and Prodromal Alzheimer’s Disease

BACKGROUND: The increasing prevalence of Alzheimer’s disease (AD) and lack of effective medications has led to a need to identify modifiable risk factors as targets for interventions. OBJECTIVE: In this cross-sectional study, we sought to determine whether worse sleep quality is associated with increased pathological tau, and whether this relationship is affected by amyloid pathology. METHODS: 66 male participants underwent Florbetapir (AV45) positron emission tomography (PET) and Flortaucipir (FTP) PET and completed the Pittsburgh Sleep Quality Index questionnaire (PSQI) as part of the Department of Defense Alzheimer’s Disease Neuroimaging Initiative, a multicenter study collecting data from Vietnam War veterans, some of whom have a history of post-traumatic stress disorder, or non-penetrating traumatic brain injury. AV45 PET was used to determine the presence of significant amyloid pathology. We used regression models to determine the effects of amyloid pathology and PSQI on tau deposition in brain regions associated with Braak stages. RESULTS: Among the 66 participants, 14 individuals were amyloid positive (21%) and 52 were amyloid negative (79%). In regions associated with Braak stages III-IV, there was a significant interaction of amyloid status on PSQI (β= 0.04, p = 0.003) with higher PSQI correlating with higher FTP SUVr in amyloid-positive individuals only (β= 0.031, p = 0.005). CONCLUSION: Our study found that an AD profile of tau deposition was associated with an interaction between self-reported sleep quality and amyloid pathology such that worse self-reported sleep was related to higher tau in regions usually associated with AD progression, but only in individuals with high cerebral amyloid deposition.