The twelve items included in the employed questionnaire clustered into three components: work-related demands(WD) (four items on high physical demands, time pressure, worries about mistakes, exposure to abusive language), interpersonal resources (IR) (five items on respectively support, recognition, adequate payment, workers’ trust in the management, and the management's trust in workers, as perceived by the workers), and work-related values (WV) (three items on job security, promotion prospects, and job latitude). A sum score was calculated for each component. Higher scores indicate higher work-related demands, interpersonal resources and work-related values, respectively.