Summary of results describing the relationships between BMI z-score and lifestyle behaviours, for different activity, screen time, sleep levels and dietary groups: β coefficients and 95% CIs
| Model 1* | Model 2† | Model 3‡ | |
|---|---|---|---|
| Physical activity§ | |||
| Active | −0.42 (−0.65 to −0.20) | −0.42 (−0.65 to −0.20) | −1.08 (−1.55 to −0.62) |
| p Value | <0.001 | <0.001 | <0.001 |
| Screen time§ | |||
| Low ST | −0.30 (−0.53 to −0.07) | −0.29 (−0.52 to −0.06) | −0.56 (−0.85 to −0.27) |
| p Value | 0.012 | 0.014 | 0.050 |
| Sleep duration§ | |||
| Long sleep | −0.28 (−0.50 to −0.05) | −0.30 (−0.51 to −0.08) | −0.70 (−1.03 to −0.37) |
| p Value | 0.015 | 0.008 | 0.193 |
| Diet§ | |||
| Mixed diet | 0.15 (−0.11 to 0.42) | 0.10 (−0.16 to 0.36) | −0.29 (−0.66 to 0.07) |
| Healthy diet | 0.05 (−0.26 to 0.36) | 0.11 (−0.20 to 0.42) | −0.20 (−0.63 to 0.24) |
| p Value | 0.489 | 0.707 | 0.823 |
| Physical activity×sleep¶ | |||
| Active, long sleep | 0.44 (0.01 to 0.87) | ||
| p Value | 0.044 | ||
| Screen time×sleep¶ | |||
| Low ST, long sleep | 0.66 (0.21 to 1.11) | ||
| p Value | 0.004 | ||
| Physical activity×diet¶ | |||
| Active, mixed diet | 0.74 (0.24 to 1.25) | ||
| Active, healthy diet | 0.53 (−0.04 to 1.10) | ||
| p Value | 0.016 | ||
Italic font indicates significant results.
*Model 1: Adjusted for age, sex and SES (parental education level), and schools are treated as random effects.
†Model 2: Mutually adjusted model with all covariates and independent variables entered simultaneously, with schools treated as random effects.
‡Model 3=Model 2 + significant interactions.
§Reference categories were inactive, high ST, short sleep and unhealthy diet, respectively.
¶Estimates refer to the specified groups. All other possible group combinations act as the referent group.
p Values are from Type 3 Tests of Fixed Effects.
BMI, body mass index; ST, screen time; SES, socioeconomic status.