Table 3.
Model 2 (primary specification) fixed effects: Unstandardized coefficients (B), 95% CIs, standardized coefficients (β*), and p-values. Reference categories: Female (sex), Year 1 (grade), 2020 (survey year).
| Predictor | B | 95% CI | β* | p |
|---|---|---|---|---|
| Intercept | 71.291 | 70.922, 71.661 | — | <0.001 |
| Grade 2 (vs 1) | 0.803 | 0.494, 1.111 | 0.042 | <0.001 |
| Grade 3 (vs 1) | 0.283 | −0.032, 0.598 | 0.014 | 0.078 |
| Grade 4 (vs 1) | 1.913 | 1.577, 2.250 | 0.092 | <0.001 |
| Sex (male vs. female) | −4.174 | −4.280, −4.068 | −0.240 | <0.001 |
| BMI (within-class) | −0.528 | −0.540, −0.515 | −0.212 | <0.001 |
| Age (centred) | −0.128 | −0.172, −0.085 | −0.023 | <0.001 |
| Class size (centred) | −0.012 | −0.023, −0.002 | −0.017 | 0.021 |
| Prop. male (centred) | 1.090 | 0.557, 1.622 | 0.033 | <0.001 |
| Mean class BMI (centred) | −0.906 | −1.080, −0.731 | −0.084 | <0.001 |
| Year 2021 (vs 2020) | 2.805 | 2.379, 3.230 | 0.123 | <0.001 |
| Year 2022 (vs 2020) | −0.372 | −0.787, 0.043 | −0.018 | 0.079 |
| Year 2023 (vs 2020) | 1.062 | 0.632, 1.492 | 0.051 | <0.001 |
| Year 2024 (vs 2020) | 3.057 | 2.642, 3.472 | 0.150 | <0.001 |