Table 3.
Coefficients, SE, and significancea of PHQ-8b, seasonality, and the interaction term between PHQ-8 and seasons in model 3c for the entire data set.
| Feature | PHQ-8, β1 (SE) | Spring, β2 (SE) | Summer, β2 (SE) | Autumn, β2 (SE) | PHQ-8 × spring β3 (SE) | PHQ-8 × summer, β3 (SE) | PHQ-8 × autumn, β3 (SE) | Likelihood ratio test (P values) |
| Sleep duration | 0.49 (0.18)** | –4.55 (2.49) | –16.27 (2.45)*** | –7.2 (2.46)** | –0.20 (0.22) | –0.04 (0.22) | 0.11 (0.21) | .50 |
| Sleep onset | 0.79 (0.22)*** | 4.57 (3.04) | 11.14 (2.98)*** | 0.55 (3) | –0.09 (0.26) | –0.41 (0.26) | –0.53 (0.26)* | .49 |
| Sleep offset | 1.01 (0.20)*** | –2.88 (2.71) | –7.28 (2.67)** | –9.74 (2.68)*** | 0.27 (0.24) | 0.04 (0.23) | 0.15 (0.23) | .53 |
| Sleep variability | 1.23 (0.19)*** | –4.32 (2.56) | 0.19 (2.52) | –1.43 (2.53) | –0.42 (0.22) | –0.57 (0.22)** | –0.14 (0.22) | .26 |
| Daily step | –73.21 (8.55)*** | 289.04 (115.3)* | 804.05 (113.32)*** | 311.21 (113.92)** | –31.51 (10.01)** | –42.61 (9.95)*** | –12.66 (9.87) | <.001 |
| Step IVd | –0.001 (0.0008) | –0.02 (0.01) | –0.06 (0.01)*** | –0.04 (0.01)*** | 0.002 (0.001)* | 0.004 (0.001)*** | 0.002 (0.001) | <.001 |
| Step ISe | –0.001 (0.0003)** | 0.01 (0.005)* | –0.001 (0.004) | 0.005 (0.004) | –0.001 (0.0004)* | –0.001 (0.0004) | –0.0001 (0.0004) | <.001 |
| L5 onsetf | 0.51 (0.29) | –4.11 (4.02) | 1.26 (3.95) | –2.89 (3.98) | 0.31 (0.35) | –0.54 (0.35) | –0.11 (0.34) | .23 |
| M10 onsetg | 0.26 (0.34) | 4.86 (4.63) | 10.33 (4.54)* | –0.44 (4.57) | 0.72 (0.41) | 1.06 (0.40)** | 0.21 (0.40) | .04 |
| HRh MESORi | –0.03 (0.01)* | –0.57 (0.16)*** | 0.05 (0.16) | 0.28 (0.16) | 0.01 (0.01) | –0.01 (0.01) | –0.03 (0.01) | .003 |
| HR amplitude | –0.04 (0.01)*** | 0.36 (0.1)*** | 0.87 (0.1)*** | 0.38 (0.1)*** | –0.02 (0.01)* | 0.01 (0.01) | 0.002 (0.008) | .001 |
| HR acrophase | 0.50 (0.30) | 40.39 (4.05)*** | 62.99 (3.98)*** | 23.3 (4)*** | 0.30 (0.35) | 0.52 (0.35) | 0.08 (0.35) | .75 |
aThe exact P values are reported in the main text.
bPHQ-8: 8-item Patient Health Questionnaire.
cModel 3: Circadian rhythm = β1 PHQ‑8 + β2 season + β3 PHQ‑8 × season + COVs, where COVs represents covariates mentioned in the Methods section. Note that winter is the reference season.
dIV: intradaily variability.
eIS: interdaily stability.
fL5 onset: the onset of least active continuous 5-hour period.
gM10 onset: the onset of the most active continuous 10-hour period.
hHR: heart rate.
iHR MESOR: midline estimating statistic of the fitted cosine wave for heart rate.
*P<.05, **P<.01, ***P<.001.