A Novel Home-Based Study of Circadian Rhythms: Design, Rationale, and Methods for the Circadia Study.

Abstract: The Circadia Study (Circadia) is a novel direct to participant research study investigating the genetics of circadian rhythm disorders. The long-term goals of this study are to better understand the genetics of circadian rhythm disorders, investigate the efficacy and accessibility of an at-home, self-directed DLMO collection, to improve health outcomes in the future for patients with circadian rhythm disorders, and to address the specific needs of the circadian rhythm disorder patient population. In this manuscript, we briefly outline the standard methods of both circadian biology research protocols and circadian rhythm disorder diagnostic procedures. We describe some of the inherent limitations of current circadian research and diagnostic methods, which motivated our development of and informed the design of the Circadia Study. We discuss the main goals of the Circadia Study, and we outline key features of our study design that build upon current study methods and address limitations. Finally, we describe specific aspects of the Circadia Study, including our study population, data collection methods, and standard operating procedures so that others may replicate aspects of the study design. Key words: Circadian rhythms; Circadian rhythm disorders; Advanced Sleep Phase Syndrome; Delayed Sleep Phase Syndrome; Non-24 Hour Sleep Wake Disorder; Melatonin; Dim Light Melatonin Onset