Sleep Duration a Factor in Childhood Obesity

Childhood obesity has more than doubled over the past three decades, which is why any study that sheds light on why this is happening is a godsend to worried parents. Science Daily, at least, has told us why children in China are obese: it’s because they go to bed late and have a shorter sleep duration. It’s a start.

So here’s the deal: scientists from the University of Birmingham in the UK found that kids in China who go to bed at a later hour and sleep fewer hours, have a tendency to be more overweight. Perhaps more interesting: even if the kids get enough sleep, later bedtimes mean they have a greater risk of obesity.

Researchers looked into the sleeping habits of 2,795 children, aged 9-12, from Guangzhou, in southern China. They found a connection between the length of sleep duration and percentage of body fat.

It turns out that Chinese children sleep even less than kids in the United States and Europe. Which is saying something, since schools in the U.S. are trending toward later school start times, because the problem of children not getting enough sleep is so prevalent. It seems that in the case of the Chinese children, however, the difference is because of the stronger focus on learning and academic achievement in China as compared to the U.S. and Europe.

The study, funded by Guangzhou Medical Foundation, had Birmingham scientists working in tandem with Chinese researchers from Sun Yat-Sen University and Guangzhou Center for Disease Control and Prevention. The upshot of their work? Kids who sleep longer, have lower Body Mass Index (BMI) scores, compared to those getting less sleep. For every one hour that sleep is put off, the BMI score increases a little bit more.

Don’t scoff at a slight increase in a BMI score. There is definite evidence that even a slight change to a BMI score matters. Such increases are considered clinically important and linked to significant changes in health status.

This study adds to the body of evidence that getting enough decent quality sleep is important for a healthy body. Sleep duration, meantime, has been on a steady decline among children and adolescents.

Sleep Duration Obesity Risk Factor

The results of this particular study were published the Journal of Epidemiology. Professor Peymané Adab, Professor of Chronic Disease Epidemiology & Public Health at the University of Birmingham commented on the study’s implications: “This study contributes to existing evidence for sleep duration as a risk factor for obesity in childhood, and later bedtime as an additional risk factor—regardless of sleep duration.

“Children in this study were getting less sleep than reported for children of similar ages in Western countries, plus their usual bedtime was relatively later than expected. These differences are likely to be cultural and due to the overemphasis on studying and academic achievement in China.”

Prof. Adab added that there are behaviors other than sleep patterns that can put children at risk for obesity, including watching television while snacking. Adab says such behavior is more common in the late evening. The researcher also suggested that children can have sleep-wake abnormalities that cause them to go to bed later.

Professor Yajun Chen, from the School of Public Health at Sun Yat-Sen University, in Guangzhou said, “There are complex factors contributing to childhood obesity including biological and lifestyle factors, but increasing observational research reports that shorter sleep duration may be an additional risk factor associated with higher body mass index (BMI) among children.”

Is your child overweight?

What time does your child go to sleep?

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About Varda Epstein

Varda Meyers Epstein serves as editor in chief of Kars4Kids Parenting. A native of Pittsburgh, Pennsylvania, Varda is the mother of 12 children and is also a grandmother of 12. Her work has been published in The Washington Post, The Huffington Post, The Learning Site, The eLearning Site, and Internet4Classrooms.