Sleep quality and shift work among South Korean public safety personnel: a cross-sectional study

Background To examine sleep quality across public safety occupations and work-schedule groups and determine whether shift work and exercise patterns were associated with poor sleep quality among South Korean public safety personnel (PSP). Methods This exploratory cross-sectional online survey included 1,403 PSP (781 military personnel, 406 police officers, and 216 firefighters); 535 office workers were included as a descriptive comparison group in Pittsburgh Sleep Quality Index (PSQI) analyses. Global and component PSQI scores were compared using conventional or Welch one-way analysis of variance with post hoc tests. Firth penalized logistic regression examined associations with poor sleep quality (PSQI > 5) among PSP, with ordinal predictors modeled categorically and monthly duty days modeled continuously. Results Poor sleep quality was identified in 1,264 PSP (90.1%) and 446 office workers (83.4%). Police officers had the highest mean global PSQI score among PSP occupations (9.42). Shift-working PSP had higher global scores than non-shift PSP (9.00 vs. 8.20; p < 0.001), but shift-work status was not associated with poor sleep quality after adjustment. In the fully adjusted model, weekly exercise frequency was associated with poor sleep quality (overall p < 0.001), although some category-specific confidence intervals were wide. Each additional monthly duty day was associated with higher odds of poor sleep quality (odds ratio [OR], 1.13; 95% confidence interval [CI], 1.01–1.28; p = 0.038). Female sex (OR, 0.65; 95% CI, 0.44–0.96) and nap durations of > 30 to < 60 min (OR, 0.42; 95% CI, 0.23–0.72) or ≥ 60 min (OR, 0.28; 95% CI, 0.15–0.51), compared with ≤ 30 min, were associated with lower odds of poor sleep quality. Conclusions Poor sleep quality was common among PSP. More detailed measures of schedule timing, workload, recovery opportunity, and activity context are needed to characterize occupational sleep burden.