Factors associated with poor sleep quality in the Korean general population: Providing information from the Korean version of the Pittsburgh Sleep Quality Index

Background: Recently, studies have been conducted to address the research gap in the understanding of poor-quality sleep and its relationship to health outcomes, through the evaluation of sleep quality. The aim of this study was to provide information regarding poor sleep quality based on a nationwide general population sample in Korea. Methods: We conducted a cross-sectional study using data from a nationwide sample of 165,193 individuals (males: 44%) aged 19 years or older from the 2018 Korea Community Health Survey. The age range of the participants was 19-107 years (mean: 55.3 +/- 17.5). The Korean version of the Pittsburgh Sleep Quality Index (PSQI) was used for assessing sleep quality. Poor sleep quality was defined as a total PSQI score of > 5. Results: The overall prevalence of poor sleepers was 41.0% (males: 35.6%; females: 46.2%). Poor socio-demographic status (illiteracy, low income, and unemployment), poor health behaviors (smoking, high-risk drinking, diabetes, hypertension, non-participation in walking, and obesity), and poor mental health (perceived poor health status, stress, depressive symptoms, and subjective cognitive decline) were all associated with poor sleep quality in both males and females. Limitations: As this study relies on self-reported and cross-sectional data, causal inferences cannot be made. Conclusions: Poor sleep quality is highly prevalent in females. In addition, poor socio-demographic status, poor health behaviors, and poor mental health were associated with poor sleep quality. The mechanisms underlying sex differences in sleep quality remain to be elucidated, and further studies are required to address this.