Table I.

Overview of health outcomes and their operationalisation.

General health	Question: ‘How would you describe your health in general? Is it. . .’ ‘Very good’, ‘Good’, ‘Fair’, ‘Poor’, or ‘Very poor’ Operationalisation: Response options ‘Fair’, ‘Poor’ and ‘Very poor’ were categorised as less than good (i.e. poor) general health
Mental health	Question battery: The general health questionnaire with 12 items (GHQ-12) Scored with the GHQ-method (0–0–1–1) in which the two first response options receive 0, and the two final response options receive 1 Operationalisation: The total score theoretically ranges between 0 and 12, in which the cut-off for poor mental wellbeing (i.e. poor mental health) was three or more points
MSP	Question: ‘During the past 3 months after work have you had pain in. . . (a) upper back or neck? (b) lower back? (c) shoulders or arms? (d) wrists or hands? (e) hips, legs, knees or feet?’ and response options ‘Every day’, ‘A couple of days per week’, ‘One day per week’, ‘A couple of days per month’ or ‘Not at all/rarely in the last three months’ Operationalisation: Response options ‘Every day’, ‘A couple of days per week’ and ‘One day per week’ on a minimum of one location was used as an indicator of pain

MSP: musculoskeletal pain.