Long Sleep Linked to Higher Alzheimer’s Biomarker in Older Adults

A new analysis of more than 2,400 participants in the Framingham Heart Study, with an average age of about 70, found a J‑shaped relationship between nightly sleep duration and blood levels of phosphorylated tau‑181 (p‑tau181), a protein linked to Alzheimer’s disease. Levels of p‑tau181 were lowest for sleep around 7–8 hours, then rose sharply after about 8½ hours and increased markedly for sleep of ten hours or more. The association persisted after adjusting for age, sex, genetic risk, depression, sleep apnea, kidney function and other factors. Researchers caution that the cross‑sectional design cannot establish causality, but suggest that unusually long sleep may be an early indicator of brain changes preceding overt memory problems. The findings were published in the journal *Alzheimer’s & Dementia*.