BACKGROUND: Approximately 2.38 million janitors are employed in the U.S. While high physical workload may explain a lost-work days rate 2.7 times greater than other occupations, little is known about the association between janitors' physical workload, mental workload, and stress. OBJECTIVE: The objective of this study was to assess the associations between physical (ergonomic) and mental workload exposures and stress outcomes among janitors. METHODS: Questionnaire data, focused on ergonomic workload, mental workload and stress, were collected from Minnesota janitors for a one-year period. Physical workload was assessed with Borg Scales and Rapid Entire Body Assessments (REBA). Mental workload assessment utilized the NASA Task Load Index (TLX). Stress assessments utilized single-item ordinal stress scale (SISS) and Perceived Stress Scale-4 (PSS-4) measures. Descriptive and multivariable analyses, including bias adjustment, were conducted. RESULTS: Odds ratios (OR) and 95% confidence intervals (CI) for ergonomic workload (task frequency) effects on SISS were: REBA (1.18 OR, 1.02-1.37 CI); Borg (1.25 OR, 1.00-1.56 CI); combined REBA and Borg (1.10 OR, 1.01-1.20 CI). Mental workload was associated with higher PSS-4 levels (0.15 Mean Difference, 0.08-0.22 CI) and a 3% increased risk for each one-unit increase in the SISS scale (1.03 OR, 1.02-1.05 CI). CONCLUSIONS: This research demonstrated a moderate effect of physical and mental workloads on stress among janitors.
Bibliographical noteFunding Information:
This project was funded by the Midwest Center for Occupational Health and Safety (MCOHS), Education and Research Center, Pilot Projects Research Training Program, supported by the National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (OH008434). The contents of this effort are solely the responsibil-
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- NASA TLX
- Perceived Stress Scale
- injury epidemiology