Abstract
BACKGROUND AND OBJECTIVES: Shorter sleep is associated with higher weight in children, but little is known about the mechanisms. The aim of this study was to test the hypothesis that shorter sleep was associated with higher energy intake in early childhood. METHODS: Participants were 1303 families from the Gemini twin birth cohort. Sleep duration was measured using the Brief Infant Sleep Questionnaire when the children were 16 months old. Total energy intake (kcal per day) and grams per day of fat, carbohydrate and protein were derived from 3-day diet diaries completed by parents when children were 21 months old. RESULTS: Shorter nighttime sleep was associated with higher total energy intake (P for linear trend=0.005). Children sleeping <10 h consumed around 50 kcal per day more than those sleeping 11-<12 h a night (the optimal sleep duration for children of this age). Differences in energy intake were maintained after adjustment for confounders. As a percentage of total energy intake, there were no significant differences in macronutrient intake by sleep duration. The association between sleep and weight was not significant at this age (P=0.13). CONCLUSIONS: This study provides the first evidence that shorter nighttime sleep duration has a linear association with higher energy intake early in life. That the effect is observed before emergence of associations between sleep and weight indicates that differences in energy intake may be a mechanism through which sleep influences weight gain.