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"Previous studies have suggested that snoring and obstructive sleep apnea...may be important risk factors for the development of carotid atherosclerosis and stroke," write Dr Sharon A. Lee, of Westmead Millennium Institute, NSW, Australia, and colleagues. However, it was unclear if snoring, in the absence of breathing interruptions (sleep apnoea), is also linked to carotid atherosclerosis.
Obstructive sleep apnoea is a common problem in which soft tissues in the back of throat repeatedly collapse during sleep causing breathing to stop for brief moments.
Snoring as well as excessive daytime sleepiness are common symptoms. The condition can be effectively treated with a small machine that blows air into the throat, preventing the tissues from collapsing.
How the study was done
In the current study, the researchers performed sleep tests to assess snoring and obstructive sleep apnea in 110 subjects. In addition, the subjects also underwent a special ultrasound test to look for carotid atherosclerosis.
The subjects were categorised into three snoring groups based on the amount of snoring: absent or mild snoring (0 to 25% of time), moderate snoring (25 to 50% of time), and heavy snoring (more than 50% of time).
Overall, 31% of subjects had carotid atherosclerosis. As night time snoring increased, the rate of atherosclerosis rose from 20 to 65%. The impact of snoring on carotid atherosclerosis was apparent even in patients without sleep apnoea.
By contrast, snoring was not associated with plaque build-up in the femoral arteries, the major vessels that supply blood to the legs.
"The importance of our findings is the implication that the risk of developing carotid atherosclerosis (and potentially stroke) is not confined to the population of patients with established obstructive sleep apnea, but also extends to the population of heavy snorers," Lee's team concludes. – (Reuters Health, October 2008)
