Sleep duration and growth outcomes across the first two years of life in the GUSTO study

Background and Aim: Short sleep duration is thought to be a factor contributing to increased body mass index (BMI) in both school-age children and adults. Our aim was to determine whether sleep duration associates with growth outcomes during the first two years of life. Study design: Participants included 899 children enrolled in the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort study. Anthropometric data (weight and body length) and parental reports of sleep duration were collected at 3, 6, 9, 12, 18, and 24 months of age. A mixed-model analysis was used to evaluate the longitudinal association of BMI and body length with sleep duration. In subgroup analyses, effects of ethnicity (Chinese, Indian, and Malay) and short sleep at three months of age (<= 12 h per day) were examined on subsequent growth measures. Results: In the overall cohort, sleep duration was significantly associated with body length (beta = 0.028, 95% confidence interval [CI] 0.002-0.053, p = 0.033), but not BMI, after adjustment for potential confounding factors. Only in Malay children, shorter sleep was associated with a higher BMI (beta = -0.042, 95% CI -0.071 to -0.012, p = 0.005) and shorter body length (beta = 0.079, 95% CI 0.030-0.128, p = 0.002). In addition, shorter sleep was associated with a higher BMI and shorter body length in children who slept = 12 h per day at three months of age. Conclusion: The association between sleep duration and growth outcomes begins in infancy. The small but significant relationship between sleep and growth anthropometric measures in early life might be amplified in later childhood. (C) 2015 The Authors. Published by Elsevier B.V.