Table 2. Model parameter estimates for season, time and intercept terms composing the model for gastrointestinal illness consultations over all municipalities, Norway, week 30 2010–week 11 2022 (n = 356 municipalities).
| Covariate | Parameter estimate | 95% CI | p value |
|---|---|---|---|
| Intercept | −5.11 | −5.120 to −5.100 | < 0.0001 |
| Time trend | −0.017 | −0.019 to −0.015 | < 0.0001 |
| Seasonal components | NA | NA | < 0.0001 |
| Sine (2*pi*time/52) | 0.047 | 0.043 to 0.052 | NA |
| Cosine (2*pi*time/52) | 0.017 | 0.013 to 0.022 | |
| Sine (4*pi*time/52) | 0.036 | 0.031 to 0.040 | |
| Cosine (4*pi*time/52) | 0.120 | 0.110 to 0.120 | |
| Sine (6*pi*time/52) | 0.004 | −0.001 to 0.007 | |
| Cosine (6*pi*time/52) | 0.061 | 0.057 to 0.066 | |
| COVID-19 era intercept | −0.63 | −0.650 to −0.610 | < 0.0001 |
| COVID-19 era time trend | 0.063 | 0.030 to 0.096 | < 0.0001 |
| Random effect variance | 0.058 | NA | NA |
| Overdispersion parameter | 0.070 | 0.068 to 0.073 | < 0.0001 |
CI: confidence interval; COVID-19: coronavirus disease; NA: not applicable; pi: 3.14.
The COVID-19 era intercept term and time trend were parametrised to begin 15 March 2020.