Chronic insomnia linked to higher dementia risk in older adults

A longrunning U.S. study of older adults found that chronic insomnia was associated with a roughly 40 percent greater risk of developing mild cognitive impairment or dementia over about five years, researchers said, and that people with persistent sleep loss showed brain changes linked to Alzheimer disease. The Mayo Clinic investigators followed 2,750 cognitively healthy adults, average age about 70, as part of the Mayo Clinic Study of Aging and reported the results in Neurology and in statements accompanying the study.

At the start of followup, 16 percent of participants met criteria for chronic insomnia. By the end of the observation period, 14 percent of those with chronic insomnia had developed dementia or mild cognitive impairment, compared with 10 percent of those without insomnia. After adjusting for age, use of sleep medications and other sleep disorders, the team calculated a 40 percent higher risk that the researchers and the American Academy of Neurology characterized as roughly equivalent to about 3.5 years of additional brain aging.

The investigators also examined brain imaging from many participants and found that people with chronic insomnia who reported sleeping...