Sleep and weight-related factors in youth: A systematic review of recent studies.

There has been much speculation about mechanisms driving the pediatric sleep/obesity link. However, conjectures have not been matched by a systematic review of pediatric data investigating sleep and behaviors directly influencing weight. This raises the risk of biased, "cherry-picked" interpretations and hampers focused research efforts. This systematic review synthesized recent studies, discussed literature gaps, and provided recommendations for future research on sleep and weight-related factors in youth. Of the 4,302 articles (published between 2012 and 2017) initially screened, 86 were included in this review, which investigated the relationship between sleep and dietary intake, altered eating behavior, physical/sedentary activity, or hormones regulating hunger/satiety. Despite prior systematic reviews indicating associations with body mass, this systematic review of proposed mechanisms revealed highly variable findings and studies showed a high risk of bias. There were some consistent patterns showing no cross-sectional association between sleep duration and caloric intake (despite experimental evidence), and shorter or later sleep associating with greater sedentary or screen time. Considerable variability in methodology, weak sleep and dietary intake measurement, and a paucity of longitudinal or experimental designs likely contributed to variability in results. Findings highlight the need for more rigorous measurement and design methods in order to move the field forward.