Association between sleep timing shifts and dietary quality in Korean high school girls during COVID-19: a cross-sectional study.

Abstract

Background/objectives: Owing to coronavirus disease 2019 (COVID-19), the shift from offline to online classes has caused significant changes in high school students' daily habits, including sleep patterns and dietary intake. This study explored the association between sleep schedule fluctuations and dietary quality among high school girls during the COVID-19 pandemic. This study examined the association between bedtime, wake-up time, and adolescent dietary quality during the weekly online/offline school period among 517 high school girls in Incheon, South Korea.

Subjects/methods: The participants were divided into 2 groups: normal sleepers (n = 244), who maintained normal sleep schedules defined as a midpoint between bedtime and wake-up time before 5:30 a.m., during in-person and online classes; and late sleepers (n = 273), who maintained a normal sleep schedule during in-person classes but exhibited late sleep patterns defined as a midpoint after 5:30 a.m., during online classes.

Results: Shorter sleep duration was characteristic of late sleepers with circadian rhythm disruption, who also displayed poorer dietary quality, including higher consumption of caffeinated beverages and street food and never consuming breakfast. Among the 5 constituent factors, disrupted sleep timing was associated with lower Nutrition Quotient for Adolescents scores in total, moderation, and environment. This association persisted independent of the grade level, even after adjusting for school grade. These findings highlight the significant effect of sleep patterns on dietary habits.

Conclusion: This study highlights the significant relationship between disrupted circadian rhythms and poor dietary quality among high-school girls. These findings reveal the need for interventions to promote healthy sleep patterns as a strategy to improve the dietary quality and overall health of adolescents.