Study objectives: Sleep problems are experienced by a large part of the population. Work characteristics are potential determinants, but limited longitudinal evidence is available to date, and reverse causation is a plausible alternative. This study examines longitudinal, bidirectional relationships between work characteristics and sleep problems.
Design: Prospective cohort/two-wave panel.
Participants: 3065 working men and women approximately representative of the Swedish workforce who responded to the 2006 and 2008 waves of the Swedish Longitudinal Occupational Survey of Health (SLOSH).
Measurements and results: Bidirectional relationships between, on the one hand, workplace demands, decision authority, and support, and, on the other hand, sleep disturbances (reflecting lack of sleep continuity) and awakening problems (reflecting feelings of being insufficiently restored), were investigated by structural equation modeling. All factors were modeled as latent variables and adjusted for gender, age, marital status, education, alcohol consumption, and job change. Concerning sleep disturbances, the best fitting models were the "forward" causal model for demands and the "reverse" causal model for support. Regarding awakening problems, reciprocal models fitted the data best.
Conclusions: Cross-lagged analyses indicates a weak relationship between demands at Time 1 and sleep disturbances at Time 2, a "reverse" relationship from support T1 to sleep disturbances T2, and bidirectional associations between work characteristics and awakening problems. In contrast to an earlier study on demands, control, sleep quality, and fatigue, this study suggests reverse and reciprocal in addition to the commonly hypothesized causal relationships between work characteristics and sleep problems based on a 2-year time lag.
Keywords: Workplace; causation; control; demand; reciprocal; reverse; sleep; sleep disturbances; structural equation modeling; support.