THE RELATIONSHIPS OF INSOMNIA AND SHORT SLEEP
TO ALL-CAUSE MORTALITY AND HEALTH-OUTCOME
DETERIORATION HAVE BEEN REPORTED FOR SOME
DECADES.1-8 Suka et al reported that persistent insomnia had
a significant relationship to hypertension.1
In a meta-analysis,
Schwarts et al reported that there was a significant relationship
between insomnia and cardiovascular disease.2
But several studies
have reported that there is no association between mortality
and insomnia.3-6
For short sleep, Liu et al have reported that less than 5 hours
of sleep had a significant relationship with acute myocardial infarction.7
Ayas et al have also reported that women who sleep 5
hours per day have a significant positive risk of coronary events
compared with women who sleep 8 hours per day.8
Kripke et al
reported that people reporting less than 3.5 or 4.5 hours of sleep
have a significantly increased mortality risk.3,4
The effect of high stress as a risk factor for sleep disturbance
has been reported in some previous studies.9-11 Tachibana et al
reported that perceived overinvolvement in the job is associated
with difficulty in falling asleep and early-morning arousal