Effort reward imbalance, and salivary cortisol in the morning.

Background: Effort reward imbalance (ERI) is suggested to increase risk for stress and is hypothesized to increase cortisol levels, especially the awakening cortisol response, ACR.

Methods: In 2006 and 2008, 480 individuals collected saliva samples at awakening and 30 min post-awakening. Mixed effects models with subject as a random effect and appropriate covariates were used to evaluate associations between the Effort Reward Model, and salivary cortisol at awakening (S0), and ACR.

Results: ERI was negatively and significantly associated with S0 for women and positively associated with ACR. S0 and ACR increased significantly from 2006 to 2008.

Conclusion: ERI was significantly associated with cortisol levels at awakening (inverse association) for women, and positively associated with ACR. The population experienced a significant increase in morning cortisol levels and ACR from 2006 to 2008, which may originate in a re-organization of the included work places.