Getting Insufficient Sleep in Middle Age Linked with Increased Dementia Risk Later On

Health experts recommend that all adults log at least seven hours of sleep a night. Sufficient sleep can help you get sick less often, remain at a healthy weight, reduce stress, and make better decisions. However, not sleeping enough can lead to plenty of problems, possibly even an increased risk of dementia.

Researchers from University College London and INSERM looked at the sleeping habits of people in their 50s and 60s and discovered that those who got six or fewer hours of sleep per night were more apt to develop dementia. The findings were recently published the journal Nature Communications.


Dr. Séverine Sabia from UCL Epidemiology & Public Health and INSERM served as lead author on the study.

She says, “Sleep problems are known to occur in people with dementia, but it remains unclear whether sleep duration in midlife affects the risk of developing dementia at older ages. Here, by using a very long follow-up period, we have found that short duration sleep in midlife, assessed more than 25 years before mean age at dementia onset, is associated with dementia risk in late life.

“While we cannot confirm that not sleeping enough actually increases the risk of dementia, there are plenty of reasons why a good night’s sleep might be good for brain health. These findings confirm the importance of sleep hygiene for health.”

To conduct the research, data from nearly 8,000 British adults who took part in the Whitehall II cohort study were used. That’s a long-running health study that has investigated topics including stress and aging. The participants had self-reported their sleep duration six times between 1985 and 1988, when they ranged in age from 35 to 55, and from 2015 through 2016, when they were between the ages of 63 and 86. Some also wore watch accelerometers to get a more objective figure. These steps allowed the team to look at the sleep patterns of each person at the age of 50, 60, and 70.


By 2019, 521 of the participants had developed dementia. Those who had gotten six or fewer hours of sleep each night during middle age were found to be 30% more likely to develop dementia as they aged than those who had had at least seven hours. There did not appear to be a connection between dementia and sleeping for eight or more hours. Researchers found this increased risk across the board and did not see different numbers based on mental health, heart health, or any specific demographics.

Dr. Archana Singh-Manoux from UCL Epidemiology & Public Health and INSERM, senior author, says, “We know that sleep is important to our brain health, as it is involved in learning and memory, waste clearance from the brain, and the ability of our brain cells to remain healthy. A better understanding of how sleep features might shape our risk of dementia is needed, as this might help researchers develop new ways to reduce the risk of dementia, or to delay its progression.”

Other studies have found an increased risk of dementia in elderly people who reported five or fewer hours of sleep a night.

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