In the largest sleep laboratory study of its kind, Penn State College of Medicine researchers have shown that people who snore, especially the young with no other sleep disorder problems, were one and a half times more likely to have high blood pressure (hypertension) than those who didn't snore.
In addition, the five-year study showed that the hypertension risk increased with the severity of the sleep problem. For example, people who snore and also have mild sleep apnea, a breathing pause, were two and a half times as likely to be affected by hypertension as those with no problems. Snorers with moderate to severe sleep apnea were seven times more likely to develop hypertension compared with those with no sleep problems.
"We were able to establish the association between sleep disorder breathing (SDB) and hypertension while adjusting for possible confounding factors such as age, weight and gender. This study indicates that if you have any kind of breathing disturbance during sleep, even just snoring, you need to be aware that you are at much higher risk for hypertension and the problems it causes," explains Edward O. Bixler, Ph.D., professor of psychiatry and study director.
Bixler and his colleagues' paper titled, "Association of Hypertension and Sleep Disorder Breathing," is published in the August 14 issue of the journal Archives of Internal Medicine.
The study included 741 men and 1,000 women ranging in age from 20 to 100. Subjects were selected based upon the presence of risk factors for SDB, such as snoring, daytime sleepiness and obesity. Subjects were evaluated during one night in the sleep laboratory at The Milton S. Hershey Medical Center. Patients were classified into one of four categories: those with moderate to severe sleep apnea, those that snored and had mild apnea, those that only snored and those with no SDB problems.
The researchers report that the strength of the association between SDB and hypertension appears strongest in the young, especially those of normal weight. In commenting on the results, Claude Lenfant, M.D. director of the National Institutes of Health's National Heart, Lung and Blood Institute (NHLBI), said, "This study in combination with other recent findings strengthens the case for an association between sleep apnea and hypertension. " He added, "Dr. Bixler's work extends earlier findings with evidence that even minimal sleep disordered breathing may be a risk factor for hypertension." Hypertension is a leading cause of cardiovascular disease and stroke. Cardiovascular disease is the number one killer in the United States. About 12 million Americans have sleep apnea, a breathing disorder characterized by brief interruptions of breathing during sleep. These breathing pauses are almost always accompanied by snoring.
Bixler adds that the findings in this study suggest that physicians should consider the possibility of hypertension whenever SDB is present.
Bixler's co-authors are: Alexandros N. Vgontzas, M.D., Penn State college of Medicine; Hung-Mo Lin, Ph.D., Penn State College of Medicine; Thomas Ten Have, Ph.d. University of Pennsylvania College of Medicine; Benjamin E. Leiby,B.A. Penn State College of Medicine; and Antonio Vela-Bueno, M.D., Autonomous University, Spain.
This study was funded by grants from The National Heart, Lung and Blood Institute of The National Institutes of Health.
Note to Reporters: To speak with Dr. Bixler, call Leilyn Perri at 717-531-8606. To speak with an NHLBI expert, please contact the NHLBI Communications Office at 301-496-4236.
Journal
Archives of Internal Medicine