While obstructive sleep apnea has been shown by previous studies to be linked to increased risks of hypertension and atherosclerosis,  Susan Redline, from Case Western Reserve University (Ohio, USA), and colleagues studied whether sleep apnea is associated with increased stroke risk in the general population.  The team assessed data collected on of 5,422 men and women, ages 40 and older, enrolled in the Sleep Heart Health Study.  Following the subjects for approximately nine years, the researchers found that men with moderate to severe sleep apnea were about three times more likely to have a stroke, as compared to men with mild or no sleep apnea.  Among women with obstructive sleep apnea, the increased risk of stroke was significant only in cases of severe apnea.