Short sleep duration linked to dementia, death in older adults

Sleeping fewer than 5 hours per night was associated with increased risks for incident dementia and death among older adults in the United States, according to research published in Aging.

“Our findings illuminate a connection between sleep deficiency and risk of dementia and confirm the importance of efforts to help older individuals obtain sufficient sleep each night,” Rebecca Robbins, PhD, an instructor in medicine at Brigham and Women's Hospital and Harvard Medical School, said in a press release.

Robbins and colleagues collected data from the National Health and Aging Trends Study, a nationally representative survey of Medicare beneficiaries aged 65 years and older. In the 2013 and 2014 surveys, a random subset of the study population received sleep questionnaires, which included questions on sleep duration, sleep latency and other sleep characteristics, such as difficulty maintaining alertness, sleep quality, napping and snoring.

The researchers evaluated the relationship between sleep disturbance, duration and other characteristics and incident dementia and all-cause mortality through 2018.

A total of 2,812 older adults were included in the final sample.

Robbins and colleagues determined that, within the final sample, incident dementia was associated with sleep duration of 5 hours or less (HR = 2.04; 95% CI, 1.26-3.33) and sleep latency longer than 30 minutes (HR = 1.45; 95% CI, 1.03 - 2.03) in adjusted Cox models.

Additionally, in adjusted models, all-cause mortality was associated with difficulty in maintaining alertness on some days (HR = 1.49; 95% CI, 1.13 - 1.94) and most or every day (HR = 1.65; 95% CI, 1.17 - 2.32), napping on some days (HR = 1.38; 95% CI, 1.03 - 1.85) or most or every day (HR = 1.73; 95% CI, 1.29 - 2.32), poor sleep quality (HR = 1.75; 95% CI, 1.17 - 2.61) and sleep duration of 5 hours or less (HR = 2.38; 95% CI, 1.44 - 3.92).

“This prospective study reveals that sleep deficiency at baseline, when the average age of participants was 76 years old, was associated with double the risk of incident dementia and all-cause mortality over the next 4 to 5 years,” Charles Czeisler, MD, PhD, FRCP, FAPS, a professor of sleep medicine in the division of sleep medicine at Harvard Medical School, said in the press release. “These data add to the evidence that sleep is important for brain health and highlight the need for further research on the efficacy of improving sleep and treating sleep disorders on the risk of Alzheimer's disease and mortality.”

References:

Newswise. Nightly sleep of five hours, less, may increase risk of dementia, death among older adults. https://www.newswise.com/articles/nightly-sleep-of-five-hours-less-may-increase-risk-of-dementia-death-among-older-adults. Accessed February 18, 2021.

Robbins R, et al. Aging. 2021;doi:10.18632/aging.202591.