Linear and nonlinear relations between psychosocial job characteristics, subjective outcomes, and sickness absence: baseline results from SMASH. Study on Musculoskeletal Disorders, Absenteeism, Stress, and Health.

This study investigates the demand-control-support (DCS) model by (a) using a more focused measure of job control, (b) testing for interactive and nonlinear relationships, and (c) further extending the model to the prediction of an objective outcome measure (i.e., company-administrated sickness absence). Hypotheses were tested in a heterogeneous sample of 1,739 employees from a 3-year prospective cohort study called SMASH (Study on Musculoskeletal Disorders, Absenteeism, Stress, and Health). Baseline results showed that a linear additive model was superior for job satisfaction, psychosomatic health complaints, and sickness absence, whereas a curvilinear model was superior for emotional exhaustion and depression. It is concluded that, first, there was no evidence of interactive effects. Second, it seems sensible to pay more attention to curvilinear relationships in future research. Finally, the DCS model was not supported using a more objective outcome measure.