Inadequate sleep and poor eating behaviours are associated with higher risk of childhood overweight and obesity. Less is known about the influence sleep has on eating behaviours and consequently body composition. Furthermore, whether associations differ in boys and girls has not been investigated extensively. We investigate associations between sleep, eating behaviours and body composition in cross-sectional analysis of 5-year-old children. Weight, height, BMI, mid upper arm circumference (MUAC), abdominal circumference (AC) and skinfold measurements were obtained. Maternal reported information on child's eating behaviour and sleep habits were collected using validated questionnaires. Multiple linear regression examined associations between sleep, eating behaviours and body composition. Sleep duration was negatively associated with BMI, with 1-h greater sleep duration associated with 0·24 kg/m2 (B = 0·24, CI -0·42, -0·03, P = 0·026) lower BMI and 0·21 cm lower (B = -0·21, CI -0·41, -0·02, P = 0·035) MUAC. When stratified by sex, girls showed stronger inverse associations between sleep duration (h) and BMI (kg/m2) (B = -0·32; CI -0·60, -0·04, P = 0·024), MUAC (cm) (B = -0·29; CI -0·58, 0·000, P = 0·05) and AC (cm) (B = -1·10; CI -1·85, -0·21, P = 0·014) than boys. Positive associations for 'Enjoys Food' and 'Food Responsiveness' with BMI, MUAC and AC were observed in girls only. Inverse associations between sleep duration and 'Emotional Undereating' and 'Food Fussiness' were observed in both sexes, although stronger in boys. Sleep duration did not mediate the relationship between eating behaviours and BMI. Further exploration is required to understand how sleep impacts eating behaviours and consequently body composition and how sex influences this relationship.
Keywords: Body composition; Children; Eating behaviours; Sleep duration.