Janitors’ mental workload, psychosocial factors, physical fitness, and injury: The SWEEP study

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Highlights

  • Among 2.4 million janitors employed in the United States, a lost work-day rate is three times greater than for other occupations.

  • To investigate the impact of non-physical workload factors on injuries among janitors, a rigorous rigorous one-year study was conducted.

  • Decreased risks of injury were associated with increased job satisfaction and increased physical fitness.

  • An important increased risk of injury was associated with increased mental workload.

Abstract

Approximately 2.4 million janitors work in the United States. High physical workload may explain a lost-work days rate 2.7 times that of other occupations. Information is limited about non-physical workload factors for janitors and their relations to injuries. For this retrospective cross-sectional study, specially designed, pre-tested questionnaires were distributed to full-time janitor members of a union for two six-month sequential intervals. Questions addressed mental workload (modified NASA Task Load Index), job satisfaction (Andrews and Withey Job Satisfaction Scale), stress (Perceived Stress Scale-4 [PSS-4], and the Single Item Stress Scale [SISS]), physical fitness, and occupational injury experiences. Descriptive and multivariable analyses, with bias adjustment, were conducted. A decreased risk of injury was associated with increased job satisfaction (expressed as a risk ratio (RR): 0.91 [95% confidence interval (CI): 0.83, 0.97]) and increased physical fitness (0.89, [0.83, 0.96]). A highly suggestive increased risk of injury was associated with increased mental workload (1.07, [1.00, 1.15]).

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

References (72)

  • M. Bagheri Hosseinabadi et al.

    The associations of workload, individual and organisational factors on nurses' occupational injuries

    J. Clin. Nurs.

    (2019)
  • Nonfatal Occupational Injuries and Illnesses Requiring Days Away from Work

    (2016)
  • Janitors and Building Cleaners : Occupational Outlook Handbook U.S

    (2018)
  • B.L. Braun et al.

    Injury events: utility of self report in retrospective identification in the USA

    J. Epidemiol. Community Health

    (1994)
  • Carl J. Caspersen et al.

    Physical activity, exercise, and physical fitness: definitions and distinctions for health-related research

    Publ. Health Rep.

    (1985)
  • C.F. Chabris et al.

    The Invisible Gorilla: and Other Ways Our Intuitions Deceive Us

    (2011)
  • M.S. Christian et al.

    Workplace safety: a meta-analysis of the roles of person and situation factors

    J. Appl. Psychol.

    (2009)
  • S. Cohen

    Perceived Stress Scale

    (1994)
  • S. Cohen et al.

    A global measure of perceived stress

    J. Health Soc. Behav.

    (1983)
  • N.A. Connelly et al.

    Assessing the relative importance of recall bias and nonresponse bias and adjusting for those biases in statewide angler surveys

    Hum. Dimens. Wildl.

    (2000)
  • A.L. Elo et al.

    Validity of a single-item measure of stress symptoms

    Scand. J. Work. Environ. Health

    (2003)
  • M.R. Endsley

    Measurement of situation awareness in dynamic systems

    Hum. Factors

    (1995)
  • S. Folkman

    Stress: appraisal and coping

  • M. Frankenhaeuser

    The psychophysiology of workload, stress, and health: comparison between the sexes

    Ann. Behav. Med.

    (1991)
  • B.J. Gabbe et al.

    How valid is a self reported 12 month sports injury history?

    Br. J. Sports Med.

    (2003)
  • T.J. Gabbett et al.

    Relationships between training load, injury, and fitness in sub-elite collision sport athletes

    J. Sports Sci.

    (2007)
  • V.J. Gawron

    Human Performance, Workload, and Situational Awareness Measures Handbook

    (2000)
  • S.G. Gerberich et al.

    Injuries among children and youth in farm households: regional Rural Injury Study-I

    Inj. Prev.

    (2001)
  • B. Gillet et al.

    Convergent and discriminant validities of corresponding job descriptive Index and Minnesota satisfaction questionnaire scales

    J. Appl. Psychol.

    (1975)
  • L. Gordis

    Epidemiology

    (2013)
  • E. Habibi et al.

    Relationship between mental workload and musculoskeletal disorders among Alzahra Hospital nurses

    Iran. J. Nurs. Midwifery Res.

    (2015)
  • J.A. Hanley et al.

    Statistical analysis of correlated data using generalized estimating equations: an orientation

    Am. J. Epidemiol.

    (2003)
  • S.G. Hart

    Nasa-task load Index (NASA-TLX): 20 years later

    Proc. Hum. Factors Ergon. Soc. Annu. Meet.

    (2006)
  • E. Hassan

    Recall bias can be a threat to retrospective and prospective research designs

    Internet J. Epidemiol.

    (2005)
  • T. Heir et al.

    Injury proneness in infantry conscripts undergoing a physical training programme: smokeless tobacco use, higher age, and low levels of physical fitness are risk factors

    Scand. J. Med. Sci. Sports

    (2007)
  • J.M. Hootman et al.

    Association among physical activity level, cardiorespiratory fitness, and risk of musculoskeletal injury

    Am. J. Epidemiol.

    (2001)
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