Is there an association between adolescent sleep restriction and obesity

This is the first prospective study of the reciprocal association between sleep restriction and weight among adolescents. Evidence on sleep duration and obesity in youth is sparse and the results have been equivocal.

Data are from a community-based, two-wave cohort study. The setting was a metropolitan area with a population of over 4 million. The cohort consisted of 4175 youths 11-17 at baseline and 3134 of these followed up a year later. Obesity was defined as body mass index >95th percentile for children of the same age and sex. Sleep restriction was defined as 6 or fewer hours of sleep per night on weeknights or on both weekends and weeknights. Covariates examined were age, gender, family income and depression.

Results clearly demonstrated that there was no association between sleep restriction and obesity at baseline. In prospective analyses, sleep restriction did not increase future risk of obesity, nor did obesity increase risk of future sleep restriction.

These findings call into question previous research based primarily on cross-sectional data suggesting a positive correlation between sleep restriction and obesity. However, the results for adolescents in this study are supported by one study of adolescents and by studies of adults using prospective designs. At this point, there appears to be little evidence for a temporal relation between sleep duration and obesity among adults or adolescents.