Overview
- Researchers followed 2,750 cognitively healthy adults, average age 70, for a mean of 5.6 years, with 16% meeting criteria for chronic insomnia.
- Chronic insomnia was defined as difficulty sleeping at least three nights per week for three months or longer.
- During follow-up, 14% with chronic insomnia developed mild cognitive impairment or dementia versus 10% without insomnia, reflecting an association rather than proof of cause.
- Shorter sleep and insomnia correlated with greater amyloid plaque burden and more white matter hyperintensities, pointing to Alzheimer-type and small-vessel vascular processes.
- Effects were stronger in APOE‑E4 carriers, and the risk increase was estimated to mirror roughly 3–4 years of additional brain aging; experts caution that randomized trials are needed and recommend CBT‑I as first-line care for insomnia.