Abstract
CONTEXT: Short sleep duration is associated with obesity, but few studies have examined the relationship between obesity and specific physiological stages of sleep. OBJECTIVE: To examine specific sleep stages, including rapid eye movement (REM) sleep and stages 1 through 4 of non-REM sleep, in relation to overweight in children and adolescents. DESIGN, SETTING, AND PARTICIPANTS: A total of 335 children and adolescents (55.2% male; aged 7-17 years) underwent 3 consecutive nights of standard polysomnography and weight and height assessments as part of a study on the development of internalizing disorders (depression and anxiety). MAIN OUTCOME MEASURES: Body mass index (calculated as weight in kilograms divided by height in meters squared) z score and weight status (normal, at risk for overweight, overweight) according to the body mass index percentile for age and sex. RESULTS: The body mass index z score was significantly related to total sleep time (beta = -0.174), sleep efficiency (beta = -0.027), and REM density (beta = -0.256). Compared with normal-weight children, overweight children slept about 22 minutes less and had lower sleep efficiency, shorter REM sleep, lower REM activity and density, and longer latency to the first REM period. After adjustment for demographics, pubertal status, and psychiatric diagnosis, 1 hour less of total sleep was associated with approximately 2-fold increased odds of overweight (odds ratio = 1.85), 1 hour less of REM sleep was associated with about 3-fold increased odds (odds ratio = 2.91), and REM density and activity below the median increased the odds of overweight by 2-fold (odds ratio = 2.18) and 3-fold (odds ratio = 3.32), respectively. CONCLUSIONS: Our results confirm previous epidemiological observations that short sleep time is associated with overweight in children and adolescents. A core aspect of the association between short sleep duration and overweight may be attributed to reduced REM sleep. Further studies are needed to investigate possible mechanisms underpinning the association between diminished REM sleep and endocrine and metabolic changes that may contribute to obesity.