Abstract
OBJECTIVES: Sleep duration, quality, and consistency are associated with overall physical health in adolescence, yet the effects of sleep on development may be not uniform because both sleep and physical health vary systematically along gradients of family income. To understand "for whom" sleep may be particularly beneficial, the present study tested family income as a moderator of relations between youth sleep and physical health. METHODS: Three hundred twenty-three youth (M age=17.39years; 53% female; 41% Black, 59% White) wore wrist actigraphs for 1week at home. Four well-recognized sleep parameters were derived: minutes, efficiency, long wake episodes, and variability in minutes across the week. Parents reported family income, and mothers rated adolescents' physical health. In independent path models, physical health was regressed onto each indicator of sleep, family income, and Sleep × Family Income interactions to test potential moderation effects. RESULTS: Associations between sleep and physical health were moderated by family income. Lower sleep efficiency, more long wake episodes, and more variability in sleep minutes were associated with poorer physical health among adolescents from lower-income families. At optimal levels of all sleep variables, income-based differences in physical health were mitigated. Youth from higher-income families tended to have better physical health regardless of their sleep. CONCLUSIONS: Findings build evidence that sleep has relations with physical health for low-income youth in particular. Clinicians and other service providers working with youth might benefit from considering the role of sleep in prevention and interventions programs geared toward improving health.