Table 3. Age-adjusted mean (standard error) of salivary cortisol according to the Effort–Reward Imbalance (ERI) model indicators and time.
| Cortisol (nmol/l) by time | Interaction (ERI indicator × time) | Main effect of ERI indicator | |||||
|---|---|---|---|---|---|---|---|
| ERI indicator | 9:00 | 12:00* | 15:00* | F (degrees of freedom) | P | F (degrees of freedom) | P |
| High effort | 0.523 (1.80, 186.7) | 0.574 | 2.681 (1, 104) | 0.105 | |||
| Absent | 3.7 (0.4) | 1.9 (0.2) | 1.9 (0.1) | ||||
| Present | 3.7 (0.4) | 2.1 (0.2) | 1.8 (0.1) | ||||
| Low reward | 0.149 (1.79, 186.4) | 0.840 | 0.501 (1, 104) | 0.481 | |||
| Absent | 3.7 (0.4) | 2.0 (0.2) | 2.0 (0.1) | ||||
| Present | 3.6 (0.4) | 2.1 (0.2) | 1.7 (0.1) | ||||
| High E/R ratio | 0.056 (1.79, 186.5) | 0.930 | 3.825 (1, 104) | 0.053 | |||
| Absent | 3.7 (0.4) | 2.1 (0.2) | 1.9 (0.1) | ||||
| Present | 3.7 (0.4) | 2.0 (0.2) | 1.8 (0.1) | ||||
| High OC | 0.515 (1.79, 186.1) | 0.578 | 0.146 (1, 104) | 0.703 | |||
| Absent | 3.7 (0.4) | 2.0 (0.2) | 1.9 (0.1) | ||||
| Present | 3.7 (0.4) | 2.0 (0.2) | 1.8 (0.1) | ||||
E/R ratio: effort-to-reward ratio; OC: overcommitment to work. F- and P-values were computed with mixed-model analyses of variance, into which age, employment status, current smoking, menstruation irregularity, ovulatory phase, musculoskeletal symptoms, dental and gum diseases, and other health problems were entered as covariates.
*: P < 0.001 for the within-subject comparison to 9:00, regardless of the ERI model indicators (paired samples t-test with the Bonferroni correction).