Sleep disparities' role in adolescent fatigue and functioning: A mixed-methods study - Abstract: Fatigue is a frequently reported complaint of adolescents and is linked to a wide range of adverse health, behavioral, and functional outcomes. Disparities in fatigue prevalence exist, with greater frequency seen in minority, economically disadvantaged populations. Disparities in sleep quantity and quality also fall along ethnic and economic lines, with poorer sleep observed among the economically disadvantaged and persons of color. Because of fatigue’s strong link with inadequate sleep, our understanding of fatigue will benefit from greater awareness of its relationship with sleep disparities, especially among early adolescents, when notable racial differences in sleep duration and timing emerge. Numerous social-environmental factors in individual, household, and neighborhood levels may serve as risk and resilience factors shaping disparities in sleep and fatigue. Yet, the relative contributions of these factors are yet unclear. Moreover, the association between inadequate sleep and fatigue is obscured by another common teen complaint: daytime sleepiness. The relationship between fatigue and sleepiness, and their differential effects on adolescent health and functioning are yet unclear. Our study purpose is to identify key mechanisms underlying racial and economic disparities in sleep and their association with fatigue, daytime sleepiness, and functioning in early adolescents. We posit that differences in household organization, socioeconomic disadvantage, and experiences of discrimination are key drivers of sleep disparity between African American and White adolescents. Guided by a community advisory board, and using a novel smart phone/sensor technology developed in our pilot research on adolescent sleep, we propose a home-based study among African American and White adolescents in Cleveland, OH to (a) identify factors responsible for adolescent sleep disparities; (b) determine the effects of sleep disparities on fatigue, daytime sleepiness, and functioning; and (b) disentangle effects of sleepiness from fatigue. Using a mixed-methods design and sample of 350 adolescents and caregivers balanced by race and socio-economic status, we will conduct linear mixed modeling to assess associations between baseline (time-invariant) and nightly (time-varying) measures of key mechanisms with that of sleep quality and quantity, fatigue, sleepiness, and functioning over a 2-week period. A qualitative study component will focus on how household/neighborhood factors and discrimination shape sleep, the teen experience of sleepiness vs. fatigue, and self-management strategies to address problematic sleep and fatigue. The study is innovative: it simultaneously investigates multiple potential mechanisms driving adolescent sleep disparities and uses novel technology to better measure the context of teen sleep. Expected results will be significant: identifying drivers of sleep disparities is vital to improve sleep, reduce fatigue and sleepiness, and improve adolescent health, functioning, and quality of life. Moreover, disentangling fatigue from daytime sleepiness is needed because their clinical implications and treatment differ.