Linking insufficient sleep with body weight in Black emerging adults. - PROJECT ABSTRACT Compared to peers in other racial groups, Black emerging adults (18-28 years old) have the highest risks of short sleep duration and obesity. This increased risk may be partly explained by greater stress levels resulting from race-related stress (feelings of discrimination and heightened vigilance) and living in more disadvantaged home and neighborhood environments. Insufficient sleep (longer sleep-onset latency, shorter sleep duration, poorer sleep quality and efficiency, less slow-wave sleep, and more severe sleep-disordered breathing) may also impact obesity risk via several weight-related mechanisms. These include (a) energy balance (difference between energy intake and energy expenditure), (b) appetite and food reward, (c) cortisol awakening response and diurnal cortisol profiles, and (d) hydration status. We will prospectively assess effects of insufficient sleep, race-related stress and living in more disadvantaged home and neighborhood environments on weight-related mechanisms and obesity markers (body weight, waist circumference and fat mass) in 150 Black emerging adults. Participants will complete 3, 7-day data collection bursts over 1 year (baseline, 6-month, and 12-month follow- up). Insufficient sleep variables will be measured with 3 methods: sleep diary, actigraphy and polysomnography. Self-report and objective methods will be used to assess weight-related mechanisms. Race-related stress will be self-reported. Home and neighborhood environments (via the Windshield Survey) will be observer-assessed. Aim 1 will examine prospective effects of insufficient sleep on weight-related mechanisms and obesity markers. Aim 2 will examine prospective effects of race-related stress and living in more disadvantaged home and neighborhood environments on insufficient sleep variables, weight-related mechanisms, and obesity markers. Aim 3 will assess the mediating role of sleep on associations among race-related stress, living in more disadvantaged home and neighborhood environments, weight-related mechanisms, and obesity markers. Our overarching hypothesis is that higher amounts of insufficient sleep and race-related stress and living in more disadvantaged home and neighborhood environments will be associated with (a) greatest energy intake and positive energy balance, (b) greatest appetite and food reward, (c) flattest diurnal cortisol profiles and lowest cortisol awakening response, (d) lowest hydration, and (e) greatest weight gain, waist circumference and fat mass at 1 year. This proposal, led by an Early-Stage Investigator and submitted in response to PAR-20-164 (Mechanisms and Consequences of Sleep Disparities in the U.S.), could have significant public health implications by identifying how and why insufficient sleep increases obesity risk in Black emerging adults.
