LAUSR

OBJECTIVE/BACKGROUND Studies focusing on insomnia in adolescents are relatively scarce compared to those on excessive daytime sleepiness. We aimed to investigate the prevalence of insomnia symptoms and associated factors in Korean high school students. PATIENTS/METHODS A total of 8565 students (girls: 4104) were investigated nationwide, across 15 South Korean districts using an online self-report questionnaire. Insomnia symptoms were evaluated using the Global Sleep Assessment Questionnaire. The participants' mean age was 16.77 ± 0.85 years. RESULTS The prevalence of insomnia symptoms was 39.43% (n = 3377). Logistic regression was used to estimate the odds ratio (OR) of insomnia symptoms associated with sleep characteristics and social behaviors after adjusting for the relevant covariates. Evening preference (OR, 2.51, 95% CI, 2.20-2.86), perception of insufficient sleep (OR, 3.55, 95% CI, 3.11-4.06), snoring usually/always (OR, 1.25; 95% CI, 1.00-1.55), witnessed sleep apnea usually/always (OR, 1.70; 95% CI, 1.17-2.46), increased internet addiction (OR, 1.02; 95% CI, 1.02-1.03), bad sleep environment (OR, 1.77; 95% CI, 1.50-2.10), ≥3 private extra classes (OR, 1.23; 95% CI, 1.01-1.49), often coffee consumption (OR, 1.31; 95% CI, 1.10-1.56), and often nocturnal eating (OR, 1.24; 95% CI, 1.06-1.45) were associated with insomnia symptoms. Evening preference (OR, 3.48; 95% CI, 2.52-4.82) was also associated with insomnia symptoms in the perceived sufficient sleep subgroup. CONCLUSION Insomnia symptoms were common in Korean high school students. Evening preference was the major factor associated with insomnia symptoms. Various socio-behavioral factors were also associated with insomnia symptoms.