Associations of self-rated health, depression, and work ability with employee control over working time.

Objectives: Work-time control (WTC), defined as employees' ability to influence their work schedules, is a crucial determinant of work-life balance and well-being. This study aims to evaluate the associations between WTC and health-related outcomes among Korean workers and examine potential effect modifications by working hours and shift work status.

Methods: This study analyzed data from the 2024 wave of the Korean Work, Sleep, and Health Study, a nationwide panel study of workers aged 19 years to 70 years (n=5,195). WTC was measured using a 6-item scale, and participants were categorized into low (≤12) or high (>12) WTC groups. Outcomes included self-rated health (SRH), depression (measured by the Patient Health Questionnaire-9), and work ability (WA; measured by the Work Ability Index). Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for poor SRH, moderate-to-severe depression, and poor WA, adjusting for demographic and occupational variables. Subgroup analyses assessed effect modifications by working hours and shift work.

Results: Higher WTC was associated with lower odds of poor SRH (OR, 0.73; 95% CI, 0.62 to 0.86), moderate-to-severe depression (OR, 0.71; 95% CI, 0.61 to 0.83), and poor WA (OR, 0.62; 95% CI, 0.46 to 0.84). These associations were significant among daytime workers but not shift workers. The protective effects of WTC were attenuated among workers whose working hours exceeding 52 hr/wk.

Conclusions: Higher WTC is associated with better health and work outcomes, emphasizing its importance for employee well-being. However, its benefits may be limited among shift workers and employees working excessive hours.