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

## TL;DR

Employees who have more control over their work schedules tend to have better health and work ability, but these benefits are weaker for shift workers and those working long hours.

## Contribution

This study identifies work-time control as a significant factor in employee health outcomes in Korea, with context-dependent effects based on working hours and shift work.

## Key findings

- Higher work-time control was linked to lower odds of poor self-rated health, depression, and work ability.
- The benefits of work-time control were strongest for daytime workers and weakened for shift workers.
- Excessive working hours (over 52 hours/week) reduced the positive effects of work-time control.

## Abstract

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.

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.

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.

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.