Long-term sleep deprivation is common in today's society. Recent experiments have
demonstrated that short-term sleep deprivation in healthy subjects results in adverse
physiologic changes, including a decreased glucose tolerance and an increased blood
pressure. However, the long-term health consequences of long-term sleep deprivation
are unclear. The objective of this study was to determine whether decreased sleep
duration (from self-reports) is associated with an increased risk of coronary events.
We studied a cohort of 71 617 US female health professionals (aged 45-65 years), without
reported coronary heart disease (CHD) at baseline, who were enrolled in the Nurses'
Health Study. Subjects were mailed a questionnaire in 1986 asking about daily sleep
duration. Subjects were followed up until June 30, 1996, for the occurrence of CHD-related
events. We assessed the relationship between self-reported sleep duration and incident
CHD.
A total of 934 coronary events were documented (271 fatal and 663 nonfatal) during
the 10 years of follow up. Age-adjusted relative risks (95% confidence intervals)
of CHD (with 8 hours of daily sleep being considered the reference group) for individuals
reporting 5 or fewer, 6, and 7 hours of sleep were 1.82 (1.34-2.41), 1.30 (1.08-1.57),
and 1.06 (0.89-1.26), respectively. The relative risk (95% confidence interval) for
9 or more hours of sleep was 1.57 (1.18-2.11). After adjusting for various potential
confounders, including snoring, body mass index, and smoking, the relative risks of
CHD (95% confidence intervals) for individuals reporting 5 or fewer, 6, and 7 hours
of sleep were 1.45 (1.10-1.92), 1.18 (0.98-1.42), and 1.09 (0.91-1.30), respectively.
The relative risk (95% confidence interval) for 9 or more hours of sleep was 1.38
(1.03-1.86).
Short and long self-reported sleep durations are independently associated with a modestly
increased risk of coronary events.