Heavy snoring linked to stroke

University of Sydney researchers have found that heavy snorers have a higher risk of cholesterol plaque in the neck arteries, leading to an increased risk of stroke.

The five year study shows that objectively measured heavy snoring is an independent risk factor for early carotid atherosclerosis, a leading causing of stroke.

The researchers at the Ludwig Engel Centre for Respiratory Research (LECRR), Westmead Millennium Institute, found after adjustment for age, gender, smoking history and hypertension, heavy snoring was significantly associated with carotid atherosclerosis compared with mild snoring.

According to the study, titled ‘Heavy Snoring as a Cause of Carotid Artery Atherosclerosis’ and published in the September issue of the international journal Sleep, 60 per cent of heavy snorers had evidence of cholesterol plaque (which leads to atherosclerosis) compared to 20 per cent of light snorers.

"Our study is the first to objectively measure and quantify snoring, rather than using a questionnaire, to explore the association between snoring and carotid atherosclerosis," said lead author and study coordinator Sharon Lee.

Associate Professor John Wheatley, director of the Ludwig Engel Centre for Respiratory Research at Westmead Hospital and co-author, said: "The high prevalence of snoring in the community means that these findings have substantial public health implications for the management of carotid atherosclerosis and the prevention of stroke."

Previous studies have reported the occurrence of habitual snoring is 24 per cent in adult women and 40 per cent in adult males. Loud and frequent snoring is also a warning sign for obstructive sleep apnoea.

Over 100 individuals aged between 45 to 80 years volunteered to be part of the research project. The participants underwent polysomnography with quantification of snoring, bilateral carotid and femoral artery ultrasound with quantification of atherosclerosis and cardiovascular risk assessment. Based on results, participants were deemed mild, moderate or heavy snorers.

According to Wheatley, treatments such as weight loss, decreased alcohol intake, oral appliance therapy and continuous positive airway pressure (CPAP) therapy have all been shown to successfully reduce snoring.

"The next step would be to conduct studies on whether reducing snoring will reverse damage to the carotid arteries," concludes Wheatley.

This study was funded by the National Health and Medical Research Council and the Department of Veterans Affairs, Australia.

(Source: Sleep : University of Sydney : September 2008)