Impact of Sleep Duration on Immune Balance in Urban Children with Asthma

Project Summary / Abstract Urban children with asthma are at high risk for short sleep, due to an environment that jeopardizes sleep and asthma management. Further, this group suffers from altered immune balance, a key biological process contributing to individual differences in asthma morbidity and sleep health. Allergic asthma is a chronic inflammatory disorder driven primarily by disturbed T helper 1 (Th1)/ 2 (Th2) cytokine balance marked by Th2 cytokine (IL-4, IL-5 and/or IL-13) predominance. Experimental findings in healthy adults show that shortened sleep increases inflammatory cytokine (e.g., IL-6) and certain Th2 cytokine levels and that recovery sleep following sleep restriction promotes a return to immune balance. Whether sleep duration plays a key role in immune function and associated asthma activity in urban children with asthma remains a scientific gap. We will use an experimental design that targets sleep duration, because (1) the urban environment and asthma symptoms interact to shorten sleep, (2) sleep duration is a modifiable behavior overlooked in clinical care of urban children with asthma, and (3) experimental data are critical to test a causal link for sleep duration as a mechanism underlying immune balance and asthma. We will enroll urban children (N=204; ages 8-9 years) with persistent allergic asthma and adequate sleep duration (9-11 h) who will complete a 4-week within-subjects protocol that includes 3 scheduled experimental sleep conditions: (1) 1 week stabilized sleep (individualized; 9-11 h time in bed), (2) 1 week shortened sleep (1.5 h decrease in time in bed), and (3) 2 weeks recovery sleep (1.5 h increase in time in bed). We will monitor sleep duration (actigraphy) and lung function (home spirometry) daily and assess immune biomarkers weekly and at the midpoint of shortened sleep. To control time-in-study effects, 1/3 of our sample will receive only the stabilized sleep schedule across the 4-week protocol. In this project, we will study only urban children with allergic asthma who obtain sufficient sleep (9-11 h, within national guidelines). Our shortened sleep protocol will model the sleep loss that urban children with asthma can experience due to asthma and/or urban context. Additionally, our recovery sleep protocol simulates a sleep optimization intervention following shortened sleep in a well-controlled approach. The first aim of the study is to examine the effects of shortened sleep on immune balance [e.g., Th1 (Interferon-IFNγ)/Th2 (Interleukin-IL-4, IL-5, IL-13)R and plasma IL-6 levels]. The second aim involves determining the effects of recovery sleep on immune balance. The third aim involves examining the extent to which changes in immune balance are associated with changes in asthma-related lung function (changes in FEV1) under conditions of shortened and recovery sleep. Results from this study ultimately will support the development feasible, ecologically valid, and clinically meaningful interventions to optimize sleep duration, immune balance, and asthma in this at-risk group.