An Examination of Sleep Pattern Characteristics and Healthy Eating Index Scores Among Students in a Circadian Biology Class

Thesis (Master's)--University of Washington, 2020Introduction Sleep restriction and circadian misalignment are associated with increased risk of chronic disease, as is poor dietary quality. College students are at risk for developing restricted, irregular sleep and poor dietary habits. This study sought to determine whether sleep duration, social jetlag, and chronotype are associated with dietary quality in third- and fourth-year college students as measured by the Healthy Eating Index-2015 (HEI-2015). Methods 67 student participants collected sleep data on themselves using both an actigraphy watch and sleep diary to measure sleep duration and social jetlag. The Morningness-Eveningness Questionnaire was used to determine chronotype and two dietary recalls administered through the Automated Self-Administered 24-hour dietary assessment tool were used to calculate HEI-2015 scores. Five participants were excluded due to missing data. Linear regression was used to analyze the data from the remaining 62 participants to test for associations between sleep and circadian factors and HEI-2015 scores, adjusting for sex. Results Average sleep duration was 7.2 ± 0.9 hours on the weekdays and 8.0 ± 1.3 hours on weekend days, with an average social jetlag of 1.0 ± 1.0 hours. The average MEQ score was 46.7 ± 9.1 with the most common chronotype being neither morningness nor eveningness (MEQ score 42-58). Average HEI-2015 score was 54.1 ± 15.3 out of 100. No significant associations were detected between sleep and circadian factors and dietary quality, though chronotype neared significance for an association with HEI-2015 overall score (p=0.11). Discussion and conclusion Overall, sleep duration on weekdays and weekend days, social jetlag, and chronotype were not significantly associated with overall dietary quality as measured by the HEI-2015 in this study. Near-significant results suggest a potential positive association of MEQ score and dietary quality, but the impact of this relationship would be marginal and MEQ is intended to identify an individual’s chronotype rather than measure morningness. Dietary quality was similar to other sampled college populations, but the use of circadian biology students as a sample population may have biased the study against detecting associations given the topic matter and potentially longer sleep duration observed in this sample compared to others. Future studies should use larger sample sizes and continue to investigate potential relationships given the inconclusive nature of the current body of literature