Exposure assessment Occup Environ Med: first published as 10.1136/oemed-2015-102831 on 10 July 2015. Downloaded from ORIGINAL ARTICLE Expert ratings of job demand and job control as predictors of injury and musculoskeletal disorder risk in a manufacturing cohort Linda F Cantley,1 Baylah Tessier-Sherman,1 Martin D Slade,1 Deron Galusha,1 Mark R Cullen2 1Occupational and ABSTRACT Environmental Medicine Objective To examine associations between workplace What this paper adds Program, Yale University School of Medicine, New injury and musculoskeletal disorder (MSD) risk and expert ratings of job-level psychosocial demand and job Haven, Connecticut, USA ▸ Psychosocial hazards in the workplace are 2Stanford Center for Population control, adjusting for job-level physical demand. recognised as emerging threats to worker Health Sciences, Stanford Methods Among a cohort of 9260 aluminium well-being, but the bulk of research examining University School of Medicine, manufacturing workers in jobs for which expert ratings Stanford, California, USA adverse health and safety outcomes associated of job-level physical and psychological demand and with these hazards has relied on worker control were obtained during the 2 years following rating Correspondence to self-reports of exposures, outcomes or both, Linda F Cantley, Occupational obtainment, multivariate mixed effects models were used raising concerns that individual psychological and Environmental Medicine to estimate relative risk (RR) of minor injury and minor traits may confound reported results. Program, Yale University MSD, serious injury and MSD, minor MSD only and School of Medicine, 367 Cedar ▸ Applying an expert-based job exposure matrix serious MSD only by tertile of demand and control, St, ESHA 2nd Fl. Room 218B, for assessment of physical job demand, New Haven, CT 06510, USA; adjusting for physical demand as well as other psychological job demand and job control, [email protected] recognised risk factors. multivariate mixed effects models were used to Results Compared with workers in jobs rated as having Received 20 January 2015 examine associations between the expert low psychological demand, workers in jobs with high Revised 2 June 2015 assessments of job-level demand and control, psychological demand had 49% greater risk of serious Accepted 22 June 2015 and acute injury, and musculoskeletal disorder Published Online First injury and serious MSD requiring medical treatment, (MSD) risk, adjusting for manufacturing 10 July 2015 work restrictions or lost work time (RR=1.49; 95% CI process, plant and individual-level covariates. 1.10 to 2.01). Workers in jobs rated as having low ▸ Workers in jobs within the highest tertile of control displayed increased risk for minor injury and rated job demand showed elevated risk of minor MSD (RR=1.45; 95% CI 1.12 to 1.87) compared serious injury and serious MSD, while those in with those in jobs rated as having high control. the lowest tertile of rated job control had Conclusions Using expert ratings of job-level http://oem.bmj.com/ increased risk for minor injury and minor MSD. exposures, this study provides evidence that No interactions were observed between psychological job demand and job control contribute physical demand, psychological demand and independently to injury and MSD risk in a blue-collar job control, suggesting independent manufacturing cohort, and emphasises the importance of contribution of these exposures to injury and monitoring psychosocial workplace exposures in addition MSD risk. to physical workplace exposures to promote worker health and safety. on October 2, 2021 by guest. Protected copyright. job tasks, workplace environment, tools and equip- – With technological changes, new management ment,9 11 and of poor psychosocial working condi- ideologies, and increases in global competition for tions to work-related injury and MSD risk has been manufacturing, considerable changes in the organ- demonstrated in a number of different worker 35–7 Open Access isation and management of work have occurred, cohorts. While the contributory role of psy- Scan to access more free content requiring employees to work harder, faster, more chosocial work demands in cumulative MSD risk is productively and with less influence over daily better recognised,5612high psychological work tasks.1 Psychosocial hazards arising from demands, alone or in combination with low deci- these changing work demands have been recog- sion latitude, could alter worker vigilance to safety nised as emerging threats to physical and mental precautions and worker risk recognition, as well as health,2 with mounting evidence suggesting associa- increase worker error rates, each of which may tions between these stressors and work-related elevate risk for acute musculoskeletal as well as injury,34as well as musculoskeletal disorder (MSD) non-musculoskeletal injury. Despite recognition – risk.5 7 that physical and psychosocial workplace hazards 21213 To cite: Cantley LF, Tessier- Work-related injuries and MSDs remain a public often coexist and may be correlated, in add- Sherman B, Slade MD, et al. health concern worldwide with potentially severe ition to evidence that each contributes to injury Occup Environ Med consequences for both workers and employers.8 and MSD risk when considered separately, epi- – 2016;73:229 236. The contribution of physical hazards arising from demiological studies examining concurrent physical Cantley LF, et al. Occup Environ Med 2016;73:229–236. doi:10.1136/oemed-2015-102831 229 Exposure assessment Occup Environ Med: first published as 10.1136/oemed-2015-102831 on 10 July 2015. Downloaded from and psychosocial workplace stressors in predicting risk have injury’ variable, we identified all incidents resulting in injury or been limited.91415This gap represents a particular shortcoming MSD, and constructed incident histories for each worker in given reports suggesting a synergistic interaction between phys- each job held during the 2-year study period. The ‘case-type’ ical and psychosocial demands that may further increase risk for variable was used to differentiate minor incidents requiring only injury or MSDs,91617and reports proposing that psychosocial first aid from the more serious incidents that resulted in medical demands may contribute to stress which could alter physio- treatment, restricted work or lost work time. All minor and logical and behavioural reactions.16 18 Moreover, associations serious injuries, and minor and serious MSD incidents for each between these different sources of job strain and occupational person-job occurring between 1 January 2004 and 31 injury and MSD risk among hourly manufacturing workers has December 2005 were included for analysis. Types of injury been explored in limited reports,41920but has yet to be fully included for analysis comprised lacerations, contusions, burns, examined, and is another gap to be filled. amputations, etc, while MSDs included instantaneous strains Most research examining associations between psychosocial and sprains, non-instantaneous strain and sprains, non- job demands and injury or MSD risk has relied on self-report by instantaneous low back disorder, etc. job incumbents.321Use of self-reported measures to examine Separate analyses were conducted to examine each of the fol- such associations has raised concern that psychological traits and lowing outcomes: minor injury and minor MSD requiring first states of the individual may be the ultimate determinant for aid only; serious injury and serious MSD that required medical observed associations rather than objective aspects of the treatment, restricted work or lost work time; the subset of job.22 23 Moreover, a focus on individual-level perceptions of minor MSDs requiring first aid only, and the subset of serious exposure may foster individual-level rather than broader work MSDs that required medical treatment, restricted work or lost cultural or organisational interventions that could potentially work time. benefit more workers. To mitigate these concerns, some investiga- Expert ratings of job-level physical demand, heat exposure, tors have used expert ratings of jobs by non-incumbents, either psychological demand and job control were obtained in late alone or in combination with subjective individually rated mea- 2003 from one senior health and safety professional at each of – sures.24 26 Because subjective ratings by job incumbents are time- eight plant locations using a pilot job demand survey (table 1). consuming and can be cumbersome to obtain, their practicality The survey was introduced in an attempt to better understand and utility in modern workplaces with greater time constraints the various aspects of company jobs, not specifically to address and increasingly scarce resources is limited. Expert job-level injury risk reduction activities. Each rater was familiar with all ratings of workplace demands may offer a more cost effective plant departments and jobs, received standardised instruction and efficient mechanism to examine these exposures as determi- via teleconference as well as written instructions prior to survey nants of workplace injury risk and better illuminate opportunities completion from the lead author, and received a complete for exposure reduction to improve safety outcomes. listing of plant job titles by department for rating. The expert As companies in the manufacturing sector strive to maintain raters assigned exposure ratings to the plant jobs based on their economic viability in a globally competitive