6 Hours of Sleep or Less in Midlife Increases Dementia Risk, Study Finds

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Research on thousands of people age 50 and over found that those who slept six hours or less per night have a significantly increased risk of developing dementia by their 70s, a new study has found.

Lack of sleep in midlife increases risk of dementia, study finds

For years, researchers have sought to find out the causes of dementia, and in particular what effects sleep, if any, have on its development, the New York Times reported.

A large, new study, which looked at thousands of subjects, appears to have found a correlation between people who don’t get enough sleep in midlife, during their 50s and 60s, and the development of dementia as they age.

Researchers compared people who slept six hours or less per night to those who slept seven hours per night, CNN reported. Researchers found that people with a “sleep duration of six hours or less at age 50 and 60” correlated to a higher dementia risk. People between the ages of 50 and 70 who had persistent short sleep duration of 6 hours or less had a “30% increased dementia risk.” Further, the study found that these risks are independent of “sociodemographic, behavioral, cardiometabolic, and mental health factors.”

Connection between sleep disturbances and mental health

In order to get further clarification on the correlation between sleep and dementia, the researchers removed people who had developed mental illness before age 65.

One of the study authors, Séverine Sabia, an epidemiologist at Inserm, the French public-health research center, pointed out that depression is considered a risk factor for dimension and that “mental health disorders are quite strongly linked with sleep disturbances.” Therefore, the analysis of participants without mental illness found a similar association between short-sleepers and the increased risk of developing dementia.

Pre-dementia signs

It is already well established that changes that occur in the brain pre-dementia, such as accumulations of proteins associated with Alzheimer’s. Signs within the brain are known to begin roughly 15 to 20 years before people begin to exhibit signs of memory and thinking difficulties. Researchers now believe that sleep patterns within that same timeframe could also be considered an emerging effect of the disease.

About the study

The findings of the research were published this week in the journal Nature. The study followed nearly 8,000 people for 25 years. The study was undertaken in Britain and drew on medical records and other data from a prominent study which began in the mid-1980s British civil servants called Whitehall II. This previous research took reports on how many times the participants slept, which was filed six times between 1985 in 2016. Interestingly, by the end of that study, 521 participants had been diagnosed with dementia at an average age of 77.