Study: Sleeping less than 6 hours a night in midlife raises risk of dementia by 30%

New research has ruled that having less than six hours of sleep every night during midlife could heighten one’s chances of suffering dementia by 30 percent.

The study — published in the journal Nature Communications — followed nearly 8,000 people for 25 years. It found more dementia risk with a “sleep duration of six hours or less at age 50 and 60” unlike those sleeping seven hours.

As most dementias are characterised by pathophysiological changes over 20 years or more, studies with a longer follow-up are needed to provide an insight into the association between sleep duration and subsequent dementia.

For the latest research, the experts used data from the Whitehall II cohort study spanning 30 years to examine the association of sleep duration at age 50, 60, and 70 with incident dementia.

They also investigated whether patterns of change in sleep duration over this period were associated with dementia.

In the analyses, the researchers looked at whether or not mental disorders in midlife affect the association of sleep duration with dementia. They examined the link between objectively assessed sleep duration and risk of dementia.

The study found that short sleep duration in midlife is associated with the higher risk of dementia later in life, independently of sociodemographic, behavioural, cardiometabolic, and mental health factors.

On the findings, CNN quoted Tara Spires-Jones, deputy director of the Centre for Discovery Brain Sciences at The University of Edinburgh in Scotland, as saying: “Sleep is important for normal brain function, and it “is also thought to be important for clearing toxic proteins that build up in dementias from the brain.”

Tom Dening, who heads the Centre for Dementia at the Institute of Mental Health at the University of Nottingham in the UK, added: “Evidence of sleep disturbance can occur a long time before other clinical evidence of dementia.

He was also quoted to have further pointed out: “However, this study cannot establish cause and effect.

“Maybe it is simply a very early sign of dementia that is to come, but it’s also quite likely that poor sleep is not good for the brain and leaves it vulnerable to neurodegenerative conditions like Alzheimer’s disease.”