Snoring could be a warning sign of dementia

If your partner snores heavily in bed, you might be tempted to give them a poke in the ribs and go back to sleep.

But that irritating nocturnal drone might actually be an early warning sign of dementia, scientists have warned.

Researchers have discovered that people who have breathing problems while asleep are more likely to experience an early decline in memory and other brain functions.

In a worrying study, they found that people with sleep apnoea - a condition often typified by heavy snoring - saw a mental decline more than a decade earlier, on average, than those who had no sleep problems.

The US researchers’ results also suggested that the onset of Alzheimer’s might be accelerated among those with sleeping problems.

At least half a million Britons suffer from sleep apnoea, which is most often found in middle-aged, overweight men.

The condition causes the muscles in the airway to contract during sleep, which cuts off the air supply, usually resulting in a heavy snore.

It causes disrupted sleep and daytime exhaustion, pushing up blood pressure.

Study author Dr Ricardo Osorio, of New York University, said: ‘Abnormal breathing patterns during sleep such as heavy snoring and sleep apnoea are common in the elderly.’

The research team studied the medical histories of 2,470 people, aged 55 to 90.

Their investigation, published in the journal Neurology, found that people with sleep breathing problems were diagnosed with mild cognitive impairment at an average age of 77.

Those with no breathing problems, in comparison, did not typically see a decline until age 90 - more than a decade later.

Among that group, those who had sleep breathing problems also developed Alzheimer’s disease five years earlier than those who did not have sleep breathing problems, at an average age of 83 compared to 88.

The scientists also found that treating the problem with a night time air mask - known as continuous positive airway pressure or CPAP - saw significant results.

People treated with the machine, which pumps a steady stream of air through the mask, were diagnosed with mild cognitive impairment about ten years later than people whose problems were not treated, at age 82 instead of age 72.

Dr Osorio said: ‘The age of onset of mild cognitive impairment for people whose breathing problems were treated was almost identical to that of people who did not have any breathing problems at all.

‘Given that so many older adults have sleep breathing problems, these results are exciting - we need to examine whether using CPAP could possibly help prevent or delay memory and thinking problems.’

His team did not establish exactly why heavy snoring might cause early dementia, but previous research has established links between sleep disruption and dementia.

Dr Osorio said: ‘These findings were made in an observational study and as such, do not indicate a cause-and-effect relationship.

‘However, we are now focusing our research on CPAP treatment and memory and thinking decline over decades, as well as looking specifically at markers of brain cell death and deterioration.’

British charities last night welcomed the findings.

Dr Doug Brown, director of research and development at the Alzheimer’s Society, said: ‘Most of us don’t think of snoring as something to be concerned about but frequent, loud snoring could be a sign of sleep apnoea - a disorder that affects breathing during sleep.

‘In this study, those who reported a sleep apnoea developed cognitive decline a decade earlier than those without sleep breathing problems, but the link between sleep apnoea and Alzheimer’s disease was much less clear.

‘Several earlier studies have shown that the quantity and quality of sleep we get can have an impact on our cognitive health and as sleeping disorders are common among the elderly, it is vital that we see more research into this area.’

Dr Simon Ridley of Alzheimer’s Research UK, added: ‘This study adds to evidence that disrupted breathing during sleep could be a risk factor for memory and thinking decline in older age, but it doesn’t prove that one causes the other.

‘Despite the small sample size in this study, the researchers did try to account for other factors that may have explained the link and the findings highlight the need to delve deeper into the possible biological reasons behind this association.

‘A good supply of oxygen to the brain is vital to keep it healthy and it is interesting to see that treatment of sleep apnoea was associated with a trend towards a later onset of memory and thinking problems.’

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