“…A growing body of evidence has shown that (short or long) sleep duration [1,4â17], sleep disturbances [1,9,18] and obstructive sleep apnea (OSA) [19â26] may predict all-cause [1,9â19,21â25,27â31], cardiovascular- [1,4,10,13,16,17,19,24,29], cancer- [1,16,17,24,30] and dementia-specific [6] mortality rates. Although there are distinct definitions for sleep duration, most studies examining short [1,6,9â11,16 ] or long sleep [5,11,13,15,32] as risk factors for all-cause or cause-specific mortality rates have considered 7â8 h as the optimal range for sleep duration [33â36]. A recently published review identified 42 cohort studies that provided evidence for an inconsistently U-shaped relationship between sleep duration and mortality rate [14].…”