September 4, 2008
A five year study conducted at the Ludwig Engel Centre for Respiratory Research (LECRR), Westmead Millennium Institute has concluded that the prevalence of cholesterol plaque in the neck arteries is more than 60 per cent in people who snore heavily.
The study ‘Heavy Snoring as a Cause of Carotid Artery Atherosclerosis’ has been published in the September issue of the international journal Sleep and shows that objectively measured heavy snoring is an independent risk factor for early carotid atherosclerosis, a leading causing of stroke.
The LECRR researchers found after adjustment for age, gender, smoking history and hypertension, heavy snoring was significantly associated with carotid atherosclerosis compared with mild snoring.
“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% in adult women and 40% of adult males. Loud and frequent snoring also is a warning sign for obstructive sleep apnea. 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. “We developed a unique measure of snoring sleep time: the total number of 30-second sleep periods that contained three or more snore sounds expressed in a percentage,” explains Lee.
Prevalence of atherosclerosis was related to the snoring sleep time in a nonlinear fashion, with a stable prevalence of atherosclerosis below a snoring sleep time of 50 percent but increasing substantially for snoring sleep times greater than 50 percent.
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: National Health and Medical Research Council and the Department of Veterans Affairs, Australia