Sleep Timing is Associated with Overweight and Snack Consumption in Children and Adolescents in Southern Brazil

Sleep timing is one of the dimensions of sleep that refers to the time of day when sleep occurs. It was included in sleep-related research because of the potential associations between overweight and consumption of meals and snacks. This cross-sectional study aimed to investigate associations between sleep timing, meal and snack consumption, and weight status in 1333 schoolchildren aged 7-14 years. The midpoint of sleep was used as a sleep timing measure obtained by the midpoint between bedtime and wake-up time and classify as Early, intermediate, and Late. Schoolchildren in the Early group were less likely to be overweight (OR: 0.83, 95% CI 0.69; 0.99), had higher odds of mid-morning snack consumption (OR: 1.95, 95%CI 1.56; 2.44) and lower probability to consume the evening snack (OR: 0.75, 95%CI 0.59; 0.94) compared with the Intermediate group. The Late group had lower odds of mid-morning snack consumption (OR: 0.67, 95%CI 0.55, 0.80) than the Intermediate group. The consumption of mid-morning and evening snacks was associated with the Early and the Late midpoint of sleep. These results suggest that bedtime and wake-up time are relevant to consuming meals and snacks and may also be related to a greater probability of being overweight in children and adolescents.