0293 Associations Between Actigraphy Sleep and Weight Change over 12 Months in Black Emerging Adults; Initial Results from the SHOW Study

Abstract Introduction Despite higher risk of short sleep duration and obesity in Black emerging adults (ages 18-28 years) compared to peers in other racial groups, no study has comprehensively assessed sleep and changes in body weight and composition in this population. We examined preliminary associations between actigraphy-assessed sleep (duration, efficiency, timing midpoint, and day-to-day variability calculated as coefficients of variation) at baseline with changes in body mass index (BMI), body composition (fat mass index (FMI) and fat-free mass index (FFMI)) and waist circumference (WC) over 12 months in the Sleep, Health Outcomes and Body Weight (SHOW) study. Methods The SHOW study aims to recruit 150 Black emerging adults to evaluate 12-month changes in sleep and body weight/composition. Sleep was measured with 7-day accelerometry, and body weight, composition, and central adiposity were assessed during an in-laboratory visit. Paired t-tests assessed changes in sleep (n=41; 30 females) and body weight/composition (n=44; 32 females) from baseline to 12 months. Partial Pearson correlations assessed associations between baseline sleep and 12-month changes in body weight/composition, controlling for age and sex. Results At 12 months, BMI (26.3±1.0, 26.9±1.0 kg/m2; t(43)=2.4, p=0.01) and FMI (7.9±0.8, 8.5±0.8 kg/m2; t(43)=2.4, p=0.01) had increased, but FFMI (17.0±0.5, 17.2±0.5 kg/m2; t(43)=0.96, p=0.17) and WC (81.6±2.0, 83.2±2.5 cm; t(43)=1.6, p=0.06) did not. Over 12 months, mean sleep duration remained short (358±9, 360±11 minutes; t(40)=0.2, p=0.42), sleep efficiency poor (70.6±1.3, 70.2±1.3%; t(40)=-0.3, p=0.61) and sleep timing midpoint late (5h28AM±1h05, 5h36AM±1h06; t(40)=0.2, p=0.44). Variability in sleep duration (23.2±1.4, 22.9±1.3%; t(40)=-0.2, p=0.56), efficiency (14.7±1.0, 13.9±0.9%; t(40)=-0.5, p=0.70) and timing midpoint (21.0±1.9, 19.9±1.6%; t(40)=-0.4, p=0.67) did not change over time. Positive associations were noted between baseline sleep timing variability and changes in WC (r=0.41; p=0.006), whereas an inverse association was noted between variability in baseline sleep efficiency and changes in FMI (r=-0.31; p=0.04). Conclusion Initial evidence indicates poor sleep behaviors were coupled with weight and fat mass gains over 12 months in Black emerging adults. Furthermore, greater variability in sleep timing midpoint, but lower variability in sleep efficiency, were associated with greater increases in total and central adiposity over 12 months. Support (if any) NIH Grant R01HL163804