Short Sleep Duration in the First Years of Life and Obesity/Overweight t Study

r of life influenced weight at an early age. in a cohort study. Sleeping habits during easured at 1-, 2-, and 4-year follow-ups. lth Organization z-scores for body mass f sleep per night at any follow-up. of short sleep duration at any follow-up e (5.3%), and 302 (8%) were overweight. Among short sleepers, the prevalence ratio for overweight/obesity after adjusting for maternal and children’s char-acteristi Conclusions Children who slept for fewer than 10 hours per night at any follow-up from 1-4 years of age were more likely to be overweight or obese at 4 years of age, despite their sociodemographic and sleep characteristics. (J Pediatr 2016;168:99-103).BMI Body mass indexE xperimental studies conducted mainly among adults have suggested that curtailment of sleep may be linked to weight gain, possibly through elevation of cortisol and ghrelin levels, along with reduction of leptin levels, thereby leading to increased hunger and reduced energy expenditure.1-4 Although individual variability in sleep need is considered to be a major determinant of the number of hours slept per day, the amount of sleep considered to be physiological is around 12-15 hours for infants and 11-14 hours for toddlers.5 Regarding nighttime sleep, the average amount expected is approximately 12 hours at 1 year of age and 11 hours at 4 years of age.6 Studies have indicated that children currently have at least 30 fewer minutes of sleep per day than the recommended amount.7 This seems to be due to later onset times for sleeping, while the time schedule for waking up in the morning is maintained.6 This finding has been observed from an early age and may also play an important role in weight gain.8,9 There is divergent evidence regarding the relationship between short sleep duration and weight status in childhood,10-14 and a lack of evidence linking very early exposure to short sleep duration and weight changes before school age.2,15 The present study aimed to investigate the association between short sleep duration at any time between 1 and 4 years of age and overweight or obesity at 4 years of age. Methods This study was developed in Pelotas, a city in southern Brazil with a population of around 328 000 inhabitants,16 of whom approximately 95 % live in the urba