A prospective study of sleep duration and coronary heart disease in women.
BACKGROUND
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.


METHODS
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.


RESULTS
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).


CONCLUSIONS
Short and long self-reported sleep durations are independently associated with a modestly increased risk of coronary events.
Ayas
Najib T
NT
Division of Pulmonary Medicine, Department of Medicine, Vancouver General Hospital, 2775 Heather St, Vancouver, British Columbia, Canada V5Z 3J5. ayasnajib@pol.net
White
David P
DP
Manson
JoAnn E
JE
Stampfer
Meir J
MJ
Speizer
Frank E
FE
Malhotra
Atul
A
Hu
Frank B
FB
D000328:Adult; D003327:Coronary Disease / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012890:Sleep; D012892:Sleep Deprivation / Q000453:epidemiology*; D013997:Time Factors