Factors associated with sleep quality and mental health outcomes: A sex and age-specific interaction analysis

Objectives: This study investigated sex- and age-specific associations between sleep quality and mental health outcomes among Korean adults. Methods: Data from 231,190 adults in the 2024 Community Health Survey were analyzed using complex sample logistic regression. Poor sleep quality was defined as a Pittsburgh Sleep Quality Index ≥ 6. Mental health indicators included perceived stress, depression, suicidal ideation, and happiness index. Models were adjusted for sociodemographic and health-related covariates; including interaction analyses for sex, age, and sleep quality. Results: Female, age 30–39 years, non-metropolitan residence, low education, smoking, alcohol use, and poor subjective health were associated with poor sleep quality. Poor sleep quality was significantly associated with adverse mental health outcomes. Interaction analysis revealed that males aged < 50 years showed significant associations with multiple mental health outcomes. While females aged < 40 years showed significant associations across all indicators. Males in their 60s and those aged ≥ 70 years exhibited the strongest association with depression. For adults in their 50s, the association with happiness weakened; while associations with depression and suicidal ideation persisted. Conclusion: Poor sleep quality was associated with adverse mental health outcomes, with differential effects by sex and age. Young adults and older males were relatively vulnerable, suggesting these groups warrant targeted public health strategies.