The Association Between Chronotype, Chronic Conditions, and Poor Sleep Quality in Korea: A Population-Based Approach

Objectives: The growing use of digital devices, along with factors such as economic stress, social issues, caffeine intake, and high-fat diets, disrupts circadian rhythms and contributes to sleep deprivation. Sleep disorders can worsen conditions, such as depression and anxiety, leading to decreased performance and health issues. This study investigated the associations among demographics, socioeconomic factors, sleep duration, chronotype, chronic conditions, and sleep quality in Korea.Methods: We analysed data from the 2018 Community Health Survey (CHS) involving 96,489 males and 119,951 females. Sleep quality was assessed using the Korean version of the Pittsburgh Sleep Quality Index, with scores above 5 indicating poor quality. Participants were categorised by chronotype based on wake-up time, and self-reported sleep duration was grouped into 6 hours or less, 7–8 hours, and 9 hours or more. Chronic conditions such as hypertension and diabetes were self-reported by participants. We included sociodemographic factors and health behaviours in our analysis, employing frequency analysis, the Rao-Scott chi-square test, and multiple logistic regression.Results: Poor sleep quality (PSQ) was associated with factors such as rural residency, non-drinking, non-smoking, being underweight, having hypertension or diabetes, experiencing stress, being identified as a non-morning-type and sleeping less than 6 hours. The non-morning-type had worse sleep quality than the morning-type, regardless of sleep duration. Chronic conditions were associated with sleep quality differently based on sleep duration, affecting those with shorter sleep duration, but not those sleeping over 9 hours.Conclusions: This study emphasises the need to consider chronotypes and chronic conditions to better understand PSQ in the Korean population.