Less sleep can increase a child's risk of being
overweight or obese, according to a study by
researchers at the Johns Hopkins Bloomberg School of Public
Health. Their analysis of epidemiological
studies found that with each additional hour of sleep, the
risk of a child's being overweight or obese
dropped by 9 percent. The results are published in the
February edition of Obesity, the journal of the
Obesity Society.
"Our analysis of the data shows a clear association
between sleep duration and the risk for
overweight or obesity in children. The risk declined with
more sleep," said Youfa Wang, senior author
of the study and associate professor in the Bloomberg
School's Center for
Human Nutrition.
"Desirable sleep behavior may be an important low-cost
means for preventing childhood obesity and
should be considered in future intervention studies. Our
findings may also have important implications
in societies where children do not have adequate sleep due
to the pressure for academic excellence
and where the prevalence of obesity is rising, such as in
many East Asian countries."
"The influence of sleep quality on obesity risk is
another important area where future research
is needed," added Xiaoli Chen, the study's lead author and
a former postdoctoral fellow at the
Bloomberg School.
For the study, Wang, Chen and May A. Beydoun, a
postdoctoral fellow at the Bloomberg School,
reviewed 17 published studies on sleep duration and
childhood obesity and analyzed 11 of them in their
meta-analysis.
The recommended amount of daily sleep varied between
studies analyzed and with children's
age. Some research suggests that children under age 5
should sleep for 11 hours or more per day,
children 5 to 10 should sleep for 10 hours or more per day,
and children over 10 should sleep at least
nine hours per day. The Johns Hopkins researchers used
these suggestions for their analysis.
The results of the analysis showed that children with
the shortest sleep duration had a 92
percent higher risk of being overweight or obese compared
to children with longer sleep duration. For
children under age 5, shortest sleep duration meant less
than nine hours of sleep per day. For children
5 to 10, it meant less than eight hours of sleep per day,
and for children over 10, less than seven hours
of sleep per day. The association between increased sleep
and reduced obesity risk was strongly
associated with boys but not girls.
The study was written by Chen, Beydoun and Wang and
was supported in part by the National
Institute of Diabetes and Digestive and Kidney Diseases,
the Department of Agriculture and the
Bloomberg School.
GO TO