Sleep is imperative for health and wellness with direct impacts on brain function, physiology, emotional well-being, performance and safety when compromised. Adolescents and young adults are increasingly affected by factors affecting the maintenance of regular sleep schedules. College and university students are a potentially vulnerable population to sleep deprivation and sleep insufficiency. Possible factors that could contribute to poor sleep hygiene include, but are not limited to, academic pressures, social activities, and increased screen time. Arguably, students are still experiencing bone mineralization, until the age of 30 or even 40 years old, which makes it more important to understand the effects that altered sleep patterns could have on continued development of bone health. It is our understanding that to date, studies assessing the risk of sleep insufficiency on bone mineral density in college students have not been conducted. We hypothesized that college-aged students, between the ages of 18-25 years, with shorter sleep durations, greater sleep schedule variability, and poorer sleep environments will have significantly lower bone mineral density. ActiGraph monitoring, via a wrist ActiWatch was used to quantitatively measure sleep habits for up to 7 consecutive days. During the week-long study participants also captured their self-reported sleep data through the use of a sleep diary. Participants were measured one time within the study for bone mineral density of the lumbar spine and total hip through a dual energy x-ray absorptiometry. This was a preliminary analysis of a larger cross-sectional analysis looked at 17 participants, of which there were 14 females and 3 males, (n=5, 1 and 11 Hispanic, Black and White, respectively). The mean age of participants was 20.8±1.7 y with an average BMI of 22.9±3.2 kg/m2. ActiWatch measurement data showed a mean daily sleep duration of participants to be 437.5 ± 43.1 (372.5 – 509.4) minutes. Mean sleep efficiency (minutes of sleep divided by minutes of time in bed) and mean number of awakenings were 87.4±4.3 (75.4-93.4) minutes and 32.1±6.4 (22.3-42.7) awakenings, respectively. The median time for wake after sleep onset (WASO) was 34.5±10.5 (18.3-67.4) minutes. The mean bone mineral density (BMD) for the hips was 1.06±0.14 (0.81-1.28) g/cm2 with a mean BMD of the lumbar spine being 1.24±0.12 (0.92-1.43) g/cm2. Age-matched Z-scores of the hips was 0.31±0.96 (-1.6-2.1) and lumbar spine was 0.53 (IQR: 0.13, 0.98; -2.25-1.55). Neither sleep duration nor sleep efficiency was significantly correlated to BMD of either locations. While WASO was positively associated with hip and spine BMD, this value was not statistically significant in this population. Overall, associations between sleep and BMD of the femur and spine were not seen in this cohort. Further work utilizing a larger cohort will allow for control of covariates while looking for potential associations between bone health, sleep duration and efficiency.

The transition from high school to college (TTC) is a critical period of change, the effects of which may be exacerbated for Latino students, who often face additional minority-specific stressors, such as ethnic/racial discrimination (ERD). Research has documented links between ERD and sleep outcomes in adolescents, but less is known regarding the longitudinal impacts of ERD experiences during unique risk periods (e.g., TTC). Further, despite the central role of family in Latino adolescents’ lives, less research has explored the protective role of family factors (e.g., familism, family support) in links between ERD and Latino students’ sleep health. Thus, this study examined: 1) longitudinal associations between peer- and adult-perpetrated ERD in high school and actigraphy-measured (e.g., duration, efficiency, midpoint) and subjective sleep (e.g., problems) during the first year of college among Latino adolescents, accounting for college ERD experiences, and 2) familism and family support as potential moderators of these associations. Participants were 209 Hispanic/Latino adolescents (Mage=18.10; 64.4% female; 84.7% Mexican descent; 67.9% first-generation students) assessed at two time points (i.e., last semester of high school and second semester of college). There were no longitudinal associations between high school ERD and college sleep. However, there were concurrent associations between ERD and sleep in college. Specifically, greater college peer- and adult-perpetrated ERD were associated with less duration and lower efficiency at the same time point. Further, more college adult-based ERD was additionally linked with greater sleep problems. There were no significant moderation findings; however, the interaction between high school adult-based ERD and family support predicting college sleep problems suggested that adolescents reporting low levels of adult ERD in conjunction with higher levels of family support had the fewest sleep problems. Study findings provide additional evidence that ERD from both adults and peers is associated with reduced sleep duration and quality among Latino college students and suggest that current cultural stressors may be particularly influential on sleep during major socio-contextual shifts. These findings can inform future programs (e.g., sleep interventions) that provide support for students experiencing race-based stressors, such as ERD, to promote Latino student health and well-being.