Changes in effort-reward imbalance at work and risk of onset of sleep disturbances in a population-based cohort of workers in Denmark

• Published in: Sleep medicine. X 2020-12, Vol.2, p.100021, Article 100021
• Main Authors: Nordentoft, Mads, Rod, Naja H., Bonde, Jens Peter, Bjorner, Jakob B., Cleal, Bryan, Madsen, Ida E.H., Magnusson Hanson, Linda L., Nexo, Mette A., Sterud, Tom, Rugulies, Reiner
• Format: Article
• Language: English
• Subjects: Epidemiology; Insomnia; Nationwide; Original; Psychology; Psychosocial work environment; psykologi; Stress; Workplace
• ISSN: 2590-1427; 2590-1427
• DOI: 10.1016/j.sleepx.2020.100021

Associations between exposure to effort-reward imbalance at work (eg, high time pressure/low appreciation) and risk of sleep disturbances have been reported, but the direction of the effect is unclear. The present study investigated changes in effort-reward imbalance and risk of concomitant and subsequent onset of sleep disturbances. Participants with sleep disturbances at baseline were excluded. We included participants from a population-based cohort in Denmark (n = 8,464, 53.6% women, mean age = 46.6 years), with three repeated measurements (2012 (T0); 2014 (T1); 2016 (T2)). Changes in effort-reward imbalance (T0-T1) were categorized into ‘increase’, ‘decrease’ and ‘no change’. Self-reported sleep disturbances (difficulties initiating or maintaining sleep, non-restorative sleep, daytime tiredness) were dichotomized (presence versus absence). We regressed concomitant (T1) and subsequent (T2) sleep disturbances on changes in effort-reward imbalance (T0-T1) and calculated odds ratios (OR) and 95% confidence intervals, adjusted for sex, age, education and cohabitation. At follow-up, 8.4% (T1) and 12.5% (T2) reported onset of sleep disturbances. Increased effort-reward imbalance was associated with concomitant sleep disturbances (T1) (OR = 3.16, 2.56–3.81), whereas decreased effort-reward imbalance was not (OR = 1.22, 0.91–1.63). There was no association between increased effort-reward imbalance and subsequent sleep disturbances (T2) (OR = 1.00, 0.74–1.37). Results were similar for men and women. Increased effort-reward imbalance was associated with a three-fold higher risk of concomitant onset of sleep disturbances at two-year follow-up, but not subsequent onset of sleep disturbances at four-year follow-up, indicating that changes in effort-reward imbalance have immediate rather than delayed effects on sleep impairment. It is possible that the results from the two-year follow-up were to some extent affected by reverse causality. •Psychosocial work stressors are discussed as risk factors for sleep disturbances.•Working conditions in which efforts exceeds rewards may elicit stress.•We studied the effect of changes in stressors on sleep in a large nationwide cohort.•Effort-reward imbalance was associated with 3-fold higher risk of sleep disturbances.•Changes in stressors had immediate rather than delayed effects on sleep impairment.