Schedule-setting arrangements, short-notice work requests, and insomnia symptoms among Korean employees: a...

Schedule-setting arrangements and short-notice work requests may represent different dimensions of working-time quality. This cross-sectional study examined their associations with elevated insomnia symptoms among 25,783 employees aged 20-64 yr in the seventh Korean Working Conditions Survey. Four schedule-setting categories were retained; frequent short-notice requests occurred at least several times a month. Elevated symptoms were defined by a Minimal Insomnia Symptom Scale-based score ≥6. Type-appropriate multiple imputation and survey-weighted regression were used. Compared with company-set schedules, core-model prevalence ratios (PRs; 95% confidence intervals) were 1.24 (1.05-1.48) for fixed-schedule choice, 2.07 (1.72-2.49) for flextime within specified limits, and 1.29 (0.99-1.69) for full autonomy; frequent requests had PR 2.48 (2.05-3.01). In the most expanded model (n=25,780), flextime and frequent requests remained associated with elevated symptoms: PRs 1.59 (1.33-1.92) and 1.91 (1.59-2.30), respectively. Continuous-score findings were directionally consistent. These models estimate alternative conditional associations because added variables may be confounders or mediators. The findings support assessing schedule-setting arrangements and short-notice requests as distinct dimensions of working-time quality.