Image: PD
1. Less sleep was associated with greater increases in body mass index (BMI) of adolescents aged 14 to 18 years. Â
2. Each additional hour of sleep was associated with a decrease in BMI, with the strongest associations in individuals in the 90th BMI percentile.Â
Study Rundown: The prevalence of obesity in adolescents has tripled over the past 40 years, a trend that has paralleled decreased sleep duration in the same age group. Cross-sectional studies have found a correlation between less sleep and adolescent obesity, but this is the first longitudinal study investigating the relationship. Results from this study revealed that less sleep was associated with larger increases in the BMIs of adolescents aged 14 to 18 years. Furthermore, each additional hour of sleep was associated with a decrease in BMI, with the strongest associations found in those at the 90th BMI percentile. Possible limitations include self-reporting of height, weight, and sleep duration. Also, sleep quality and caloric intake data were not collected, but may serve as potential confounders. Nonetheless, data from this study suggest that increasing sleep duration may prevent obesity in adolescents, supporting current recommendations that adolescents sleep for 8.5 to 10.5 hours each day.
Click to read the study, published today in Pediatrics
Relevant Reading: Complications of obesity in children and adolescentsÂ
Study author, Dr. Jonathan Mitchell, PhD., talks to 2 Minute Medicine:Â Center for Clinical Epidemiology and Biostatistics, at the University of Pennsylvania
“We used quantile regression to test the association between sleep duration and specific body mass index (BMI) percentiles in a sample of adolescents.  Using quantile regression we observed an association between shorter sleep duration and increases in BMI at all percentiles.  However, the association was stronger at the upper percentiles, compared to the lower percentiles, of the BMI distribution.  Based on our findings, increasing sleep duration among adolescents could help to reduce the prevalence of obesity.”
In-Depth [longitudinal study]: The study followed the sleep patterns of 1089 14-18 year olds every six months for four years. Participants self-reported typical sleep duration, height, weight, and BMI was calculated. BMI increased on average in both adolescent boys and girls and less sleep was associated with greater increases in BMI. Additional hours of sleep were associated with reductions in BMI across all percentiles, with the strongest relationship found at the 90th BMI percentile. These participants experienced a BMI reduction of 0.28 kg/m2 per additional hour of sleep, compared to those at the 75th and 50th percentiles, with reductions of 0.25 kg/m2 and 0.15 kg/m2 per additional hour of sleep, respectively. These findings remained after adjusting for screen time and physical activity.Â
By Cordelia Ross, and Leah H. Carr
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