Chronotype is associated with eating behaviors, physical activity and overweight in school-aged children

Background Chronotype may play an important role in diverse aspects of an individual’s life. Little is known about the association between chronotype, eating habits, physical activity and obesity. Thus, this study aimed to explore the relationships between chronotype, eating behaviors, physical activity, and overweight in Chinese school-aged children. Methods Data from this study was based on 952 schoolchildren (10-12 y) from six primary schools that participated in China. Anthropometric measurements of height and body weight were performed. Information about sleeping habits, dietary behaviors, and other lifestyle behaviors was collected using a self-administered questionnaire. Multiple linear regression analysis or multivariable logistic regression model was performed to assess the associations between chronotype, eating behaviors, physical activity, and overweight. Results Nearly 70% (69.9%) of the participants had a self-reported morning chronotype. Multiple linear regression analysis revealed chronotype score was positively associated with physical activities (all P values ﹤ 0.001) and sleep duration (all P values ﹤ 0.001) and negatively associated with BMI, meal time, eating jetlag and social jetlag (all P values ﹤ 0.001). Multivariable logistic regression analysis showed that compared to morning types, non-morning types individuals were more likely to be overweight (OR= 1.65, P values ﹤ 0.05), and had more frequent consumption of fast food (OR= 1.63, P values ﹤ 0.05), sugary drinks (OR= 1.32, P values=0.057, marginally significance) and less frequent consumption of milk (OR= 0.73, P values ﹤ 0.05). Conclusions This study indicates that early chronotype children are more active, have healthier dietary habits, get more sleep, have shorter social jet lag, and are less likely to be overweight than non-early chronotype.