Report on Childhood Obesity in China (10): Association of Sleep Duration with Obesity

Objectives To explore the association of sleep duration with obesity among children in urban areas of China.Methods A total of 6 576 children(3 293 boys and 3 283 girls) aged 7-11 years were randomly selected from 36 primary schools in 6 metropolitan cities in China.A 7-day Physical Activity Recall was used to assess the sleep duration and physical activity level.The height,weight,waist circumference(WC) and percentage of body fat(%BF,as determined by bioelectrical impedance analysis technique) were measured by following the standardized operation procedures.The information on demography,lifestyle and eating habits was collected with a self-administered questionnaire from participants and their parents.Results The average sleep duration per night in the children was 9.7 h with the decreasing trends along with the increase of age(P<0.05).The sleep duration was negatively associated with body mass index(BMI) and WC in both boys and girls after adjustment for confounders(β value-0.23 and-0.82 for boys,-0.24 and-0.91 for girls,respectively,P<0.01).However,no significant association of sleep duration with %BF was found.Children who slept less than 9.0 h per night had a higher risk for overweight and obesity(OR=1.29,95% CI:1.01,1.64) and abdominal obesity(OR=1.38,95% CI:1.04,1.83) as compared with those who slept for 10.0-10.9 h.Conclusions Short sleep duration is associated with obesity.It is important to ensure adequate sleep duration of children and foster their healthy lifestyle at an early stage of life.