Janitors’ mental workload, psychosocial factors, physical fitness, and injury: The SWEEP study
Introduction
In 2016, there were 2,384,600 people employed as janitors (BLS, 2018) in the United States (U.S). Their work, involving reportedly high physical workloads, appeared to place them at risk for days away from work with a rate 2.7 times higher than all other occupations (BLS, 2016). However, little is known about non-physical workload factors and associations with injuries among janitors. Workload is a complex construct; there are many potential elements, including not only mental workload but, also, psychosocial factors, which may be related to work-related injuries (Christian et al., 2009). For example, mental workload has been shown to increase task errors and injury rates (Yurko et al., 2010; Elo et al., 2003; Frankenhaeuser, 1991), and Littman et al. (2006), reported that other psychosocial factors, including job satisfaction (Ramirez et al., 1996; Rentsch and Steel, 1992) and stress (Elo et al., 2003; Irie et al., 2001) were related to workload which, in turn, may be related to injury outcome. In addition, low physical fitness has been reported as related to injury (Knapik et al., 1993; Twitchett et al., 2010).
While the janitors’ Service Employees Union International Local 26 (SEIU L26) noted a workload measure, not familiar to the janitors, based on average square feet cleaned per person per shift, it was not known how this relates to measurements of mental workload, psychosocial factors, physical fitness, and outcome of injury. Thus, to move to the next step, the objective of this study was to identify the relations between mental workload, job satisfaction, stress, physical fitness, and injury occurrence in janitors.
Section snippets
Target population
Following approval by the University of Minnesota Institutional Review Board (Human Subjects Protection Case No. 1605P87861), the Safe Workload Ergonomic Exposure Project (SWEEP) Study, involving a closed prospective cohort study design, was initiated. The target population was the approximately 4,000 janitors who were members of SEIU L26. However, to optimize participation and retention over one year of data collection, the population was limited to the 1,200 individuals, identified by the
Questionnaire response
There was an overall response rate of 32.5% among the initial 1,200 individuals who were to have received the questionnaires. This involved 390 janitors who responded to one of the two surveys; 137 (11.4%) janitors responded to both surveys, accounting for a total of 527 completed surveys (Fig. 2).
Mental workload results
To assess mental workload, the NASA TLX was utilized (Table 1). There were 444 responses to the TLX section of the survey (approximately 100 were from the same people over both survey periods). No
Discussion
Slappendel et al. (1993), and Yurko et al. (2010), reported that increased mental workload can increase task errors and injury rates. The findings from the current study, indicating a positive association between mental workload and injury, is consistent with this literature.
Rentsch and Steel (1992) indicated that the scale used for the SWEEP study to examine job satisfaction, the Andrews and Withey Job Satisfaction Questionnaire, was significantly correlated with job performance,
Conclusions
Results from this study identified decreased risks of injury for both increased job satisfaction and increased physical fitness. Increased mental workload was associated with an increased risk of occupational injury. These findings serve as a basis for further research and opportunities for development of relevant intervention efforts.
Extension of this research to populations such as hotel housekeepers and construction workers could provide important findings where there are similar but not
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
This project was supported by the Midwest Center for Occupational Health and Safety (MCOHS), Education and Research Center, Pilot Projects Research Training Program funded by the National Institute for Occupational Safety and Health (NIOSH, Centers for Disease Control and Prevention under grant OH008434. The contents of this effort are solely the responsibility of the authors and do not necessarily represent the official view of the National Institute for Occupational Safety and Health, Centers
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