143 The Shared and Unique Genetic Influences of Pubertal Development and Objective Sleep During Middle Childhood

Introduction More advanced pubertal development has negative impacts on sleep quality and quantity in adolescents (Foley et al., 2018). Pubertal development and sleep both have high genetic influences, while environmental factors are also evident (Breitenstein et al., 2020; Dick et al., 2001). To elucidate underlying relations between pubertal development and sleep, the present study examined the genetic and environmental influences on the covariation of these health processes using a twin study design. Methods This racially and socioeconomically diverse sample included 596 twin children (Mage=8.41, SD=.69; 51.7% female; 66.3% White; 33.7% Hispanic; 156 monozygotic, 217 same-sex dizygotic, and 179 opposite-sex dizygotic). Children wore wrist-based accelerometers (Motion Logger Micro Watch; Ambulatory Monitoring, Inc, Ardsley, NY USA) on their non-dominant wrist for 7 nights (M= 6.81, SD= .67) to measure their sleep (efficiency, duration). Primary caregivers completed Zygosity Questionnaire for Young Twins (Goldsmith, 1991), as well as the Pubertal Development Scale (Petersen et al., 1988) for each twin, and puberty composite scores for males and females were used (Coleman & Coleman, 2002). Bivariate Cholesky decompositions were fit in OpenMX to estimate genetic and environmental influences on the covariance between pubertal development and sleep (Boker et al., 2011). The -2 log-likelihood chi-square test of fit and the Akaike’s Information Criterion were used to find the most parsimonious solution. Results 261 White (68.9%) and 135 Hispanic (77.1%) participants had initiated puberty. Pubertal development was positively correlated with sleep efficiency (r =.15) and sleep duration (r =.15). Pubertal development, sleep efficiency, and sleep duration were all heritable at 59%, 54%, and 73%, respectively. The AE-A-AE twin model was the best-fitting model for both bivariate models, with additive genetics accounting for 86% and 90% of the shared covariance between pubertal development and sleep efficiency and duration, respectively. Conclusion The genetic association between pubertal development and sleep suggests a third variable influence, and Wang and colleagues (2020) have identified genetic variants that partially explain the association. Future directions include longitudinal analyses across the pubertal transition as environmental demands increase. Support (if any) Supported by the US Eunice Kennedy Shriver National Institute of Child Health and Human Deve