Long Sleep Duration Linked to Increased Alzheimer’s Biomarkers

Both short and long sleep durations have been linked to the risk of Alzheimer’s disease, yet the specific nature of this relationship concerning blood-based biomarkers has not been extensively studied. Research on how sleep duration correlates with dementia risk remains inconclusive, especially with limited exploration into biomarker profiles, including glial fibrillary acidic protein (GFAP).

Researchers from the Framingham Heart Study evaluated the links between self-reported sleep duration and four plasma biomarkers—phosphorylated tau (p-tau)181, total tau (t-tau), neurofilament light chain (NfL), and GFAP—among 2,410 participants.

Using restricted cubic spline modeling, the study revealed a significant non-linear association between sleep duration and p-tau181, with a p-value of 0.005 for the overall link and 0.002 indicating non-linearity. Elevated levels of p-tau181 were observed in individuals sleeping 8.5 hours or more, even after adjusting for variables such as age, sex, apolipoprotein E ε4 genotype, sleep apnea, depression, and kidney function. A similar trend was noted for total tau, although the strength of this link decreased after adjustments. For neurofilament light chain, the associations were primarily attributable to kidney function. No significant correlations were found for shorter sleep durations.

These findings suggest that prolonged sleep duration, especially beyond 8.5 to 9 hours, might indicate early neurodegenerative changes, as the link with p-tau181 remained consistent. However, since this is a cross-sectional study, causative conclusions cannot be drawn, and the results are considered to be hypothesis-generating. The authors recommend further evaluation for individuals reporting sleep durations exceeding 9 to 10 hours, which should be followed up with future studies that incorporate objective sleep metrics and investigate emerging biomarkers like p-tau217 and p-tau231.

The study was conducted by Young VM et al. and published in Alzheimer's & Dementia: 2026; 22:e71499.