Excess Sleep Elevates Stroke Risk

Previous studies suggest a link between abnormal sleep and risk of stroke. Yue Leng, from University of Cambridge (United Kingdom), and colleagues followed just under 9692 men and women, ages 42 to 81 years, enrolled in the European Prospective Investigation into Cancer (EPIC)-Norfolk cohort over 9.5 years.  During 1998-2000 and then again four years later, the researchers asked the subjects how many hours on average they slept in a day and whether they generally slept well. Almost seven out of ten participants reported sleeping between six and eight hours a day, whilst one in ten reported sleeping for over eight hours a day. Over the almost ten year period of the study, 346 participants suffered a stroke, either non-fatal or fatal stroke. After adjusting for confounding factors, the investigators found that people who slept longer than 8 hours a day were at a 46% greater risk of stroke than average. Further, subjects who reported persistently long sleep -- in other words, they reported sleeping over eight hours when asked at both points of the study -- were at double the risk of stroke, as compared to those with persistently average sleep duration (between six and eight hours a day). The study authors submit that: “This prospective study and meta-analysis identified prolonged sleep as a potentially useful marker of increased future stroke risk in an apparently healthy aging population.”