Table 2.
Mixed Model Estimatesa (95% CI) of Screen Time (Minutes/Day), Measured by the Sedentary Behavior Log, by Study Group
| Workbook | Internet | Difference | P-value | |
|---|---|---|---|---|
| Weekly averageb | ||||
| Baseline | 136.96 (105.26, 168.65) | 110.06 (80.37, 139.74) | −26.90 (−70.30, 16.50) | 0.222 |
| Week 6 | 133.52 (100.03, 167.00) | 84.53 (53.18, 115.88) | −48.98 (−94.81, −3.16) | 0.036 |
| Week 12 | 122.66 (90.71, 154.60) | 121.91 (90.76, 153.05) | −0.75 (−45.33, 43.83) | 0.973 |
| Change from baseline | ||||
| Week 6 | −3.44 (−32.63, 25.75) P = .815 |
−25.52 (−46.13, −4.91) P = .016 |
−22.08 (−57.60, 13.43) | 0.221 |
| Week 12 | −14.30 (−39.79, 11.19) P = .268 |
11.85 (−10.20, 33.90) P = .289 |
26.15 (−7.34, 59.63) | 0.125 |
| Adjusted changec from baseline | ||||
| Week 6 | −7.50 (−40.69, 25.69) P = .656 |
−29.03 (−55.35, −2.72) P = .031 |
−21.53 (−57.51, 14.46) | 0.239 |
| Week 12 | −17.16 (−57.15, 22.84) P = .399 |
12.34 (−24.58, 49.27) P = .511 |
29.50 (−4.14, 63.13) | 0.085 |
a
Random family effect included to account for multiple children per family. Kronecker (UN@CS) covariance structure used for repeated measures within an individual (3 time points × 2 measurements per time point). Covariance matrix estimated separately for each study group. Satterthwaite correction for denominator degrees of freedom.
b
Average of 2 Sedentary Behavior Logs taken a week apart.
c
Adjusted for calendar month, age, sex, and baseline BMI-for-age z score.