OBJECTIVETo investigate the relationships of childhood obesity and the duration of sleep as well as insulin resistance.

METHODSTwo hundred and sixty-nine simple obese children aged from 7 to 15 years with body mass index(BMI) over 23 and 120 normal healthy children were recruited in this study. Obese children were divided into three groups: Group A: 23 < or = BMI < 25; Group B: 25 < or = BMI < 30; Group C: BMI > or = 30. Duration of sleep was calculated according to the reported sleeping hours during working days and weekends. Oral glucose tolerance test and insulin releasing test were performed in all obese children. Seventy of the 120 healthy children received fasting plasma glucose (FBG) and fasting insulin (FINS) detection. Homeostasis model assessment-insulin resistance (HOMA-IR) and islet beta cell secreting index (HOMA-IS) were calculated.

RESULTSThe duration of sleep was shorter in all 3 obese groups than that in the control group and the levels of FBG, FINS and HOMA-IR were higher (P < 0.05). The levels of HOMA-IS in Group B and C were higher than that in the control group (P < 0.05), while HOMA-IS did not show much difference among the 3 obese groups and between Group A and the control group (P > 0.05). Logistic analysis showed that the duration of sleep was related to childhood obese (P < 0.05). Results from multiple linear regression model analysis showed that BMI bore a relation to HOMA-IR and HOMA-IS (P < 0.05), as well as one unit increase in BMI accompanied with 0.261 and 11.054 increase in HOMA-IR and HOMA-IS, respectively.

CONCLUSIONChildren with shorter duration of sleep were susceptible to become obese. A significant correlation did exist between BMI and insulin resistance.