Sleep apnoea and risk of stroke

By Anna Sayburn

BMJ Group News

What do we know already?

Sleep apnoea is a condition that affects your breathing while you sleep. It means you stop breathing for several seconds at a time, and wake momentarily when you restart breathing. Even if you don’t remember waking up, sleep apnoea can disturb your sleep enough to make you drowsy during the day.

Sleep apnoea can be treated by wearing a mouthpiece or mask overnight, to keep the airways open.

Some research has indicated that sleep apnoea might have more serious consequences, such as making you more likely to have a stroke. But the evidence isn’t strong and we need more research to be sure.

This new study looked at people who’d had a stroke, and who were at risk of having another. They were studied in a sleep laboratory and tested for sleep apnoea. They also had CT and MRI scans, to look for evidence of damage to the brain caused by stroke.

What does the new study say?

Almost all of the stroke patients had sleep apnoea when tested in the laboratory - 51 out of 56 patients, more than nine in 10.

In addition, people with severe sleep apnoea were more likely to show signs of ‘silent strokes’ - previous strokes that had not caused any obvious problems at the time, but could be seen on brain scans. More than 5 in 10 people with signs of silent strokes had severe sleep apnoea.

The researchers say their results demonstrate that sleep apnoea should be treated as a risk factor for having a stroke, in the same way as high blood pressure.

How reliable is the research?

This study was presented at a medical conference, rather than published in a medical journal, so we’re unable to look closely at the methods and the results. For example, we don’t know if the researchers took into account any other factors that could put people with sleep apnoea at a higher risk of stroke, such as whether they were overweight, smokers, or had a previous history of heart disease. We also don’t know how people were selected to take part in the study. This means we can be less sure about how reliable the results are.

What does this mean for me?

If you or your partner has sleep apnoea, it’s important to get treatment. As well as the risk of stroke, sleep apnoea can cause accidents if people fall asleep while driving or operating machinery because of lack of sleep.