Sleeping disorders carry a link to Alzheimer’s - studies

BRITAIN: Night-time breathing problems that affect as many as one in four adults can prevent the brain clearing out noxious waste proteins associated with Alzheimer’s disease, researchers say.

Doctors are experimenting with dental shields, compressed air masks and lifestyle changes in the hope these simple steps will delay or prevent many cases of dementia.

Studies have pointed to a link between poor sleep and the onset of serious memory conditions. Findings presented at the Alzheimer’s Association international conference in London yesterday included the first strong evidence that sleep disorders can prevent the brain clearing out noxious proteins.

Scientists believe cheap sleep therapies such as continuous positive airway pressure (CPAP) devices could stop these biological signs of Alzheimer’s disease from building up, delay serious cognitive decline by several years and even preventing it altogether in some patients.

‘‘Sleep disordered breathing is treatable in many cases,’’ said Dean Hartley, director of science initiatives for the Alzheimer’s Association in Britain. ’’Through early diagnosis and effective treatment, there is the potential to improve cognition and possibly reduce dementia risk.’’

Three out of 10 men and one in five women are thought to have some kind of sleep-disordered breathing. In the most common form, known as obstructive sleep apnea, the throat muscles relax and block the airway for at least 10 seconds at a time.

Professor Michael Bubu, an applied health scientist at Wheaton College, Illinois, said this meant brain cells could not get enough oxygen, leading to an accumulation of the amyloid-beta and tau proteins that are the classic harbingers of Alzheimer’s disease.

Sleep apnea also raises inflammation and stresses neurons so that they get worse at communicating with one another.

Three teams of researchers coordinated by Bubu tracked 1639 Americans aged from their late 60s to their early 80s. Nearly half had mild memory problems; of the remainder, 325 had been diagnosed with Alzheimer’s disease and 516 were cognitively normal.

Those with sleep apnea but not Alzheimer’s developed amyloidbeta proteins at a much faster rate than those who did not have either condition, while sleep apnea seemed to make no difference to the amyloid-beta levels in patients who already had Alzheimer’s.

Another analysis showed that sleep breathing disorders in general were linked to a steep rise in amyloid-beta levels for people with normal cognition.

Bubu said the results indicated detecting and dealing with sleep apnea could be a comparatively easy way to head off dementia.

Most people with sleep apnea do not know that they have the condition: studies suggest that 82 per cent of men and 93 per cent of women are undiagnosed.

Clive Ballard, a dementia researcher at the University of Exeter who was not involved in the studies, said there was growing evidence that a range of sleep problems might lead to Alzheimer’s as well as predicting it.

‘‘There are some [animal studies] that are also beginning to suggest that it’s causative, but it’s still at a relatively early stage.’’

– The Times