Short Sleep Duration as a Risk Factor for Obesity in Childhood Is Associated with Increased Leptin, Ghrelin, and Orexin Levels

Objectives: To explore the association between short sleep duration, obesity and the role of appetiterelated hormones in 10 to 15 years old children. Design: An observational study was conducted from January 2003 to June 2010, with epidemiological survey, anthropometry, and laboratory tests. One-way logistic and linear logistic methods were used for data analysis. Participants: A total of 311 obese children aged from 10 to 15 years and 300 healthy children with normal body mass index at the equivalent ages. Measurements and Results: Life styles of all participants were surveyed by questionnaires. Fasting serum samples were collected for detection of leptin, ghrelin and orexin from 114 obese and 49 healthy children randomly selected from the patient pool. Sleep duration of obese children, usually less than 9 hours, was 1 hour shorter than that of the healthy controls (P<0.05). Compared to the children sleeping less than 8 hours, the odd ratio for susceptibility to obesity was 0.015 (95% confidence interval: 0.005-0.051) for those sleeping more than 10 hours. Linear regression revealed that shorter sleep was associated with higher serum leptin, ghrelin, and orexin levels. If children's sleep time was deprived by one hour, the level of leptin, ghrelin and orexin will increase 7.894 ng/ml, 21.716 ng/ml, and 2.409 ng/ml respectively (P<0.01). Conclusions: Children at the age of 10 to 15 years have short sleep in common and those who do not sleep sufficiently are susceptible to obesity. Serum leptin, ghrelin, and orexin levels in children were elevated when they sleep less and consequently this increased the risk of obesity.