Environmental Exposures & Sleep in the Nurses' Health Study 3

PROJECT SUMMARY The goal of this F31 fellowship application is to support and promote the training of Cindy R. Hu, currently a pre-doctoral student in the Department of Environmental Health of the Harvard TH Chan School of Public Health and the Graduate School of Arts and Sciences at Harvard University. Her long-term research interests focus on

the associations of multiple environmental exposures on sleep. Ms. Hu has assembled a group of leading experts as her Sponsors and Co-Sponsors including Drs. Jaime Hart, Brent Coull, Peter James, and Susan Redline. Sleep is an important component of human health; it is a process that serves key functions in cognition,

performance, physiological repair, and recovery. Inadequate sleep has been linked to many physical health outcomes like cardiovascular disease, diabetes, and obesity, as well as mental health outcomes such as anxiety and depression. A nation-wide analysis showed an uneven geographic distribution of insufficient sleep across

the US; this geographic variability may be explained by a confluence of social and environmental determinants of health. Environmental exposures that shape one’s sleeping environment as well as exposures that are experienced during wake can impact sleep health. Of particular interest due to their modifiability are built

environment factors, such as light at night, neighborhood greenspace, and walkability have been shown to affect sleep. Currently, environmental epidemiological studies of sleep often rely on self-reported measures of sleep. The development of mobile health technologies provides an opportunity to quantitatively measure sleep

in ecologically valid and free-living (i.e. non-laboratory) conditions on a larger scale, but requires validation against research standards. In addition to quantitative assessments of sleep, mobile health data can provide rich information on GPS location and behaviors like physical activity, which allow for investigation of

mechanisms that link environmental exposures to sleep. Another key aspect of furthering our understanding of how the environment impacts sleep is the utilization of an exposomic framework; to our knowledge, no study has examined the effects of multiple exposures on sleep. Using the unique resources of the Nurses’ Health

Study 3 (NHS3) longitudinal cohort, Ms. Hu will receive extensive training in multiple aspects of exploring the impacts of the environment on sleep, ranging from how to compare objective measures from multiple sources (Aim 1), using mobile health panel studies to examine associations between features of the built environment

on sleep outcomes (Aim 2), and how to scale these insights to a full cohort of US women and men (Aim 3). This will position her to be a future leader in the field of the environment and sleep through high-quality mentorship and extensive professional development opportunities.