Getting too little -- or too much -- sleep
may increase a person's risk of developing type 2 diabetes,
new research suggests.
"Sleep
duration may be a novel risk factor for the development
of clinical diabetes," conclude the researchers in the
March issue of Diabetes Care.
Dr. Henry
Klar Yaggi from Yale University in New Haven, Conn. and
two colleagues studied the long-term (15-year) impact
of sleep duration on the development of diabetes in more
than 1,100 middle-aged and elderly men who were free of
diabetes in 1987-1989 and were followed until 2004.
Men getting
no more than 6 hours of sleep per night, as well as those
getting more than 8 hours of shut eye per night, were
at significantly increased risk for developing diabetes,
compared to men getting 7 to 8 hours of sleep each night.
The risk
of diabetes was roughly twofold higher in men reporting
short sleep duration and more than threefold higher in
those reporting long sleep duration, compared with men
sleeping 7 to 8 hours nightly.
"This
U-shaped distribution of risk with respect to sleep duration
has been reported previously for coronary heart disease,
all cause mortality, and diabetes in women," Yaggi stated.
The elevated
risks with short or long durations of sleep "remained
essentially unchanged" after adjustment for several factors
including age, blood pressure, smoking status and waist
circumference, the authors say.
However,
relative risks were reduced "considerably" when adjusted
for testosterone, suggesting to the team that the effects
of sleep on diabetes could be mediated via changes in
the body's levels of this hormone.
