Methods A cross-sectional study was conducted in November 2007 among 470 eligible workers. Respondents
self-administered the Job Content Questionnaire downloaded from the company’s intranet. A median-split
procedure was applied to create four groups according to the Job Demand–Control Model:
active, passive, high and low job strain. Logistic regression models were used to investigate the associations
between socio-demographic, occupational and psychosocial factors and high job strain