After monitoring nearly 8,000 people for 25 years, the study found a higher risk of dementia with “sleep duration of six hours or less at the ages of 50 and 60” compared to those who slept seven hours a night.
In addition, persistently short duration of sleep between the ages of 50, 60 and 70 was also associated with a “30% increased risk of dementia,” independent of “sociodemographic, behavioral, cardiometabolic, and mental health factors,” including depression, the study said. .
“Sleep is important for normal brain function and is also believed to be important for clearing up toxic proteins that build up in the brain in dementia,” said Tara Spiers-Jones, deputy director of the Center for Discovery Brain Sciences at Edinburgh. in Scotland, in a statement. Spiers-Jones was not involved in the investigation.
“What’s the message to all of us? Evidence of sleep disturbance may well before the onset of other clinical evidence of dementia,” said Tom Dening, head of the Center for Dementia at the Institute of Mental Health at the University of Nottingham in the UK. , in a statement.
“However, this study cannot determine cause and effect,” said Denning, who was not involved in the study. “Maybe it’s just a very early sign of dementia to come, but it’s also quite likely that poor sleep isn’t good for the brain and makes it vulnerable to neurodegenerative conditions like Alzheimer’s.”
Chicken or egg?
But does poor sleep lead to dementia – and which comes first? This “chicken and egg” question has been explored in previous studies, with research pointing in both directions, said neuroscientist Jeffrey Iliff, a professor of psychiatry and behavioral sciences at the University of Washington School of Medicine.
However, some recent studies have examined the damage that sleep deprivation can cause.
A week of disrupted sleep increased the amount of tau, another protein responsible for the tangles associated with Alzheimer’s disease, frontal lobe dementia and Lewy body disease, the study found.
“The fact that we can find these effects in people who are cognitively healthy and close to middle age suggests that these relationships occur early, which may provide an opportunity to intervene,” Bendlin said.
‘New information’ on connection with sleep deprivation
Because the new study followed a large population over a longer period of time, it adds “ new information to the emerging picture ” about the link between sleep deprivation and dementia, said Elizabeth Coulthard, an associate professor of dementia neurology at the University of Bristol. UK, in a statement.
“This means that at least some of the people who developed dementia probably didn’t already have it at the start of the study when their sleep was first assessed,” said Coulthard, who was not involved in the study.
“It strengthens the evidence that poor sleep in middle age can cause or worsen dementia later in life,” she said.
Right now, science doesn’t have a “ sure way to prevent dementia, ” but people can change certain behaviors to reduce their risk, Sara Imarisio, head of strategic initiatives at Alzheimer’s Research UK, said in a statement. Imarisio was not involved in the investigation.