0059 EVALUATION OF THE SLEEP REGULARITY INDEX (SRI) AMONG FIRST YEAR COLLEGE STUDENTS: ASSOCIATION WITH ALCOHOL USE, CAFFEINE CONSUMPTION, ACADEMIC LOAD, AND NEGATIVE MOOD

Abstract

Introduction: Regularity is an important feature of sleep with associations with important domains of young-adult functioning, including mood, weight gain, and academic performance. Quantifying regularity can be challenging. The Sleep Regularity Index (SRI) compares the sleep/wake state across adjacent 24 hour periods. The index ranges from 0 (random) to 100 (perfect regularity) and is sensitive to abrupt changes to sleep schedules common during young adulthood. We evaluated the SRI among first year college students using daily diary records. Methods: Between 2009 and 2014, 1328 first year college students completed daily diaries during their first semester of college. Diaries included bedtime (BT), wake-time (WT), total sleep time (TST), sleep onset latency, and wake after sleep onset for the previous major sleep episode, as well as naps, and the number of alcohol and caffeinated drinks. In addition, participants completed a longer survey every two weeks that asked about mood and academic load. Data were aggregated across the two weeks prior to each biweekly survey where at least 50% of the diaries were completed (4275 biweekly periods from 1049 participants, 57% female, Mage=18.65). Results: Incremental value of SRI relative to BT and TST in explaining number of alcoholic and caffeinated drinks, negative mood, and academic load. Average SRI was 74.59 (SD=7.60) and was associated with BT (β=-.07[95% CI=-.11;-.04]) and TST (β=-.09[-.12;-.06]). After accounting for TST and BT, SRI was significantly related to negative mood (β=-.08[-.11;-.04]), alcoholic drinks (β=-.012[-.015;-.008]), caffeinated drinks (β=-.005[-.006;-.003]), and academic load (β=-.006[-.008;-.004]). Conclusion: The SRI calculated from daily diary records is related to important domains of young-adult functioning including alcohol use, caffeine consumption, academic load, and negative mood. Although the SRI is related to sleep duration and timing across a two-week period in this population, it provides unique information beyond these two measures. Support (If Any): This work was supported by R00HL119618 & MH079179.