Disturbed sleep linked to higher risk of stroke

ELDERLY people who sleep poorly are more likely to have severely hardened arteries, putting them at higher risk of strokes, a study has found.

Researchers believe monitoring the sleep of older people may be a way to identify who is at risk of suffering a stroke.

The findings, published in Sleep Journal Report, suggest that sleep monitoring may be another way to identify older people who could be at risk of suffering a stroke.

The academics studied the brains of old people whose sleep had been monitored before they had died. The brains were then examined under the microscope.

They found that repeatedly waking up in the night was associated with damage to blood vessels and brain tissue.

Hardened arteries – or atherosclerosis – is caused when inflammation and fatty tissue causes blockages of the blood vessels.

Poor sleep was an independent risk factor for severe atherosclerosis, separate from other factors such as body mass index (BMI), smoking history, diabetes, hypertension, and other medical conditions such as Alzheimer’s disease, pain, depression or heart failure.

Dr. Andrew Lim, lead investigator and neurology professor at the University of Toronto, said: “The forms of brain injury that we observed are important because they may not only contribute to the risk of stroke but also to chronic progressive cognitive and motor impairment.

“However, there are several ways to view these findings: sleep fragmentation may impair the circulation of blood to the brain, poor circulation of blood to the brain may cause sleep fragmentation, or both may be caused by another underlying risk factor.”

The researchers studied 315 brains of people whose average age was 90. A total of 70 per cent were women.

All had been monitored for at least one week around the clock for sleep quality while they were alive.

Some 29 per cent of the patients had suffered a stroke. A further 61 per cent had signs of moderate to severe damage to the blood vessels in the brain.

For every two arousals during one hour of sleep, researchers reported a 30 per cent increase in the odds that the subjects had visible signs of oxygen deprivation in their brain.

Greater sleep fragmentation – where the patient woke up repeatedly during the night – was associated with 27 percent higher odds of having severely hardened arteries.

Further work is needed to clarify whether brain blood vessel damage is a consequence or cause of broken sleep.

The role of specific contributors to sleep fragmentation such as sleep apnoea also need to be examined further, the researchers say.

Previous research has found that people who sleep poorly are at greater risk of inflammation of their blood vessels.

Getting less than six hours of sleep per night had a worse effect on women than men, according to a University of California study.

Researchers have found that slightly more women than men report poor sleep – 81 per cent of women versus 78 per cent of men.

Women are more likely (50 per cent) to wake up too early compared to men (41 per cent), and to have a harder time falling asleep – 33 per cent of women versus 31 per cent of men.