Short sleep duration and large variability in sleep duration are independently associated with dietary risk factors for obesity in Danish school children

BACKGROUND: Lack of sleep and increased consumption of energy-dense foods and sugar-sweetened beverages (SSBs) have all been suggested as factors contributing to the increased prevalence of overweight and obesity. OBJECTIVE: To evaluate whether objectively measured sleep duration (average and day-to-day variability) as well as parent-reported sleep problems are independently associated with proposed dietary risk factors for overweight and obesity in 8-11-year-old children. DESIGN: In this cross-sectional study, data on sleep duration and day-to-day variability in sleep duration were measured in 676 Danish, apparently healthy children by an objective measure (actigraphy) for 8 nights, and the Children's Sleep Habits Questionnaire (CSHQ) was filled out by the parents. Diet was recorded using a web-based food record for 7 consecutive days. Fasting blood samples were obtained for measurements of plasma leptin and ghrelin levels. RESULTS: Sleep duration (h per night) was negatively associated with energy density (ED) of the diet (beta = -0.32 kJ g(-1)), added sugar (beta = -1.50 E%) and SSBs (beta = -1.07 E%) (all P <= 0.003). Furthermore, variability in sleep duration (10-min per night) was positively associated with SSBs (beta = 0.20 E%, P = 0.03), independent of sleep duration, and CSHQ score was positively associated with ED (beta = 0.16 kJ g(-1), P = 0.04). All of these associations were independent of potential confounders (age, sex, pubertal status, height, weight, screen time, moderate-to-vigorous physical activity and parental education and ethnicity). CONCLUSION: Our study suggests that short sleep duration, high sleep duration variability and experiencing sleep problems are all associated with a poor, obesity-promoting diet in children.