Insomnia Moderates the Relationship Between Amyloid-β and Cognitive Decline in Late-Life Adults without Dementia

Background: It is suggested that not all individuals with elevated A beta will develop dementia or cognitive impairment. Environment or lifestyle might modulate the association of amyloid pathology with cognition. Insomnia is a risk factor of cognitive disorders including Alzheimer's disease. Objective: To investigate if insomnia moderated the relationship between amyloid-beta (A beta) and longitudinal cognitive performance in non-demented elders. Methods: A total of 385 Alzheimer's Disease Neuroimaging Initiative participants (mean age = 73 years, 48% females) who completed 4 + neuropsychological evaluations and a [F-18] florbetapir positron emission tomography scan were followed up to 8 years. Linear mixed-effects regression models were used to examine the interactions effect between insomnia and A beta on longitudinal cognitive sores, including four domains (memory [MEM], executive function [EF], language [LAN], and visuospatial function [VS]). Results: The A beta-positive status (A+) but not insomnia independently predicted faster cognitive decline in all domains. Furthermore, the relationship between A beta and cognitive decline was moderated by insomnia (MEM: chi(2) = 4.05, p = 0.044, EF: chi(2) = 4.38, p = 0.036, LAN: chi(2) = 4.56, p = 0.033, and VS: chi(2) = 4.12, p = 0.042). Individuals with both elevated A beta and insomnia experienced faster cognitive decline than those with only elevated A beta or insomnia. Conclusion: These data reinforced the values of insomnia management in preventing dementia, possibly by interacting A beta metabolism. Future efforts are warranted to determine whether sleep improvement will postpone the onset of dementia, specifically among populations in stages of preclinical or prodromal AD.

Automated summary

Insomnia may modulate the relationship between amyloid-beta and cognitive performance in older adults, with individuals having elevated A beta and insomnia experiencing faster cognitive decline.