Somatic growth of lean children: the potential role of sleep.

BACKGROUND Despite the current obesity pandemic, childhood malnutrition remains an urgent, public health concern. Similar to the obesity pandemic, childhood malnutrition is influenced by genetic and a number of social, environmental and biological factors. In this study, we investigated the association between sleep duration and somatic growth in lean children. METHODS A stratified, randomly clustered sampling design was used to select fifth grade students from 10 primary schools in Shanghai. Based on a body mass index below the 15th percentile a subsample of 143 lean children aged 10-11 years old was defined. Sleep duration and other potential confounders were surveyed through parental or self-report questionnaires. Body measurements were collected and used to calculate the Z score of weight, height, body mass index as well as body fat percentage. RESULTS Compared with children who slept <9 hours, those who slept for ≥10 hours grew taller and gained more weight after adjusting for confounding factors. When children slept 9-10 hours, they had significantly higher Z score of weight and body mass index. CONCLUSIONS Prolonged sleep not only benefits weight gain but also improves height in lean children. Our findings might provide important public health advice such that prolonged sleep may be an effective modifier of nutritional problems in childhood.