Table 4.
Coefficients, SE, and significancea of PHQ-8b, seasonality, and the interaction term between PHQ-8 and seasons in model 3c for the pre-COVID subset.
| 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) |
| Sleep duration | 0.97 (0.26)*** | –3.01 (3.99) | –14.86 (3.67)*** | –6.88 (3.45)* | –0.01 (0.34) | –0.05 (0.31) | 0.11 (0.29) |
| Sleep onset | 0.87 (0.36)* | –2.1 (5.46) | 9.84 (5.02) | 0.58 (4.73) | –0.25 (0.46) | –0.51 (0.43) | –0.64 (0.39) |
| Sleep offset | 1.43 (0.31)*** | –6.17 (4.65) | –7.6 (4.27) | –10.04 (4.03)* | –0.24 (0.39) | –0.22 (0.36) | 0.07 (0.34) |
| Sleep variability | 1.47 (0.26)*** | 1.94 (4.09) | 2.29 (3.76) | 0.62 (3.55) | –0.76 (0.35)* | –0.89 (0.32)** | –0.33 (0.3) |
| Daily step | –71.62 (12.05)*** | 657.17 (179.07)*** | 1096.36 (164.67)*** | 321.63 (155.06)* | –20.45 (15.21) | –48.65 (13.99)*** | 1.49 (12.91) |
| Step IVd | –0.001 (0.001) | –0.04 (0.02)* | –0.03 (0.02) | –0.01 (0.02) | 0.004 (0.002)* | 0.003 (0.001)* | 0.0007 (0.0013) |
| Step ISe | –0.0003 (0.0005) | –0.004 (0.0072) | 0.0021 (0.0066) | 0.0035 (0.0063) | –0.0003 (0.0006) | –0.0007 (0.0006) | –0.0002 (0.0005) |
| L5 onsetf | 0.57 (0.45) | –17.84 (7.16)* | –6.74 (6.58) | –2.26 (6.22) | 0.4 (0.61) | –0.2 (0.56) | –0.17 (0.52) |
| M10 onsetg | 0.09 (0.51) | –7.37 (7.89) | 4.83 (7.25) | 1.28 (6.84) | 1.14 (0.67) | 1.22 (0.62)* | 0.07 (0.57) |
| HRh MESORi | –0.08 (0.02)*** | –0.4 (0.27) | –0.53 (0.25)* | –0.38 (0.23) | 0.01 (0.02) | 0.04 (0.02)* | 0.04 (0.02)* |
| HR amplitude | –0.05 (0.01)*** | 0.31 (0.17) | 0.58 (0.15)*** | 0.07 (0.14) | –0.01 (0.01) | 0.02 (0.01) | 0.02 (0.01) |
| HR acrophase | 0.52 (0.38) | 35.11 (5.77)*** | 68.14 (5.3)*** | 22.2 (5.0)*** | 1.15 (0.49)* | 0.26 (0.45) | 0.19 (0.42) |
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.
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.