Table 5.
Mean changes in study variables at post-intervention and 6- and 12-month follow-up for boys only.
| Study Group | Difference in Change Score | ||||||
|---|---|---|---|---|---|---|---|
| Control | Intervention | (Group 1—Group 0) | |||||
| Outcome | n | M (SD) | n | M (SD) | M (95% CI) | Effect Size | p (Two-Tailed) |
| Primary and secondary outcomes | |||||||
| Weight/shape concerns | |||||||
| Baseline | 163 | 1.15 (1.41) | 217 | 1.14 (1.35) | |||
| Post-intervention | 165 | 1.03 (1.29) | 202 | 1.20 (1.52) | 0.18 [−0.04, 0.41] | 0.131 | 0.116 |
| 6-month follow-up | 153 | 1.10 (1.31) | 179 | 1.18 (1.37) | 0.14 [−0.10, 0.38] | 0.102 | 0.261 |
| 12-month follow-up | 150 | 1.05 (1.28) | 193 | 1.19 (1.38) | 0.19 [−0.08, 0.46] | 0.138 | 0.160 |
| State body satisfaction | |||||||
| Baseline | 163 | 71.44 (30.33) | 217 | 69.34 (30.89) | |||
| Post-intervention | 165 | 72.43 (30.19) | 203 | 70.73 (30.22) | −0.23 [−5.52, 5.05] | −0.008 | 0.932 |
| 6-month follow-up | 152 | 75.26 (29.19) | 178 | 73.92 (27.39) | −0.66 [−6.46, 5.14] | −0.022 | 0.823 |
| 12-month follow-up | 149 | 74.35 (29.03) | 191 | 72.75 (27.44) | −0.31 [−6.56, 5.94] | −0.010 | 0.922 |
| Dietary restraint | |||||||
| Baseline | 162 | 1.82 (0.88) | 216 | 1.79 (0.88) | |||
| Post-intervention | 164 | 1.69 (0.89) | 202 | 1.75 (0.92) | 0.13 [−0.01, 0.28] | 0.148 | 0.074 |
| 6-month follow-up | 153 | 1.73 (0.92) | 179 | 1.75 (0.88) | 0.09 [−0.10, 0.28] | 0.102 | 0.338 |
| 12-month follow-up | 149 | 1.59 (0.81) | 193 | 1.67 (0.87) | 0.20 [0.00, 0.40] | 0.227 | 0.049 |
| Drive to increase muscularity | |||||||
| Baseline | 162 | 11.90 (5.65) | 217 | 11.11 (5.42) | |||
| Post-intervention | 164 | 10.96 (5.87) | 202 | 10.79 (5.50) | 0.72 [−0.19, 1.64] | 0.130 | 0.122 |
| 6-month follow-up | 153 | 11.23 (5.89) | 179 | 11.12 (5.17) | 0.91 [−0.24, 2.06] | 0.165 | 0.123 |
| 12-month follow-up | 150 | 10.93 (6.03) | 192 | 11.08 (5.06) | 1.61 [0.41, 2.81] | 0.292 | 0.008 |
| Self-esteem | |||||||
| Baseline | 160 | 11.74 (2.79) | 213 | 11.06 (2.65) | |||
| Post-intervention | 162 | 11.85 (2.77) | 198 | 11.10 (2.77) | 0.06 [−0.47, 0.59] | 0.022 | 0.821 |
| 6-month follow-up | 153 | 11.13 (3.01) | 175 | 11.26 (3.02) | 0.78 [0.17, 1.39] | 0.288 | 0.012 |
| 12-month follow-up | 146 | 11.46 (3.13) | 191 | 11.02 (3.00) | 0.38 [−0.27, 1.03] | 0.140 | 0.254 |
| Depressive symptoms | |||||||
| Baseline | 159 | 14.65 (6.47) | 214 | 14.78 (6.36) | |||
| Post-intervention | 164 | 15.10 (7.64) | 202 | 15.42 (7.50) | 0.08 [−1.31, 1.47] | 0.012 | 0.910 |
| 6-month follow-up | 153 | 14.86 (7.23) | 177 | 14.95 (7.17) | 0.17 [−1.21, 1.56] | 0.027 | 0.807 |
| 12-month follow-up | 147 | 15.40 (7.60) | 190 | 16.62 (7.64) | 1.31 [-.21, 2.82] | 0.204 | 0.091 |
| Exploratory outcomes | |||||||
| Thin ideal internalization | |||||||
| Baseline | 162 | 10.50 (4.77) | 218 | 11.14 (4.60) | |||
| Post-intervention | 163 | 11.04 (4.58) | 203 | 11.44 (4.53) | −0.09 [−0.97, 0.79] | −0.019 | 0.843 |
| 6-month follow-up | 152 | 11.65 (4.81) | 179 | 11.07 (4.47) | −0.79 [−1.77, 0.18] | −0.169 | 0.112 |
| 12-month follow-up | 149 | 10.93 (4.84) | 191 | 11.69 (4.58) | 0.37 [−0.64, 1.39] | 0.079 | 0.469 |
| Muscular internalization | |||||||
| Baseline | 162 | 12.69 (5.81) | 218 | 12.11 (5.48) | |||
| Post-intervention | 165 | 12.11 (6.16) | 204 | 11.89 (5.60) | 0.21 [−0.79, 1.21] | 0.037 | 0.682 |
| 6-month follow-up | 153 | 12.61 (6.19) | 179 | 12.58 (5.79) | 0.53 [−0.62, 1.69] | 0.094 | 0.363 |
| 12-month follow-up | 149 | 12.00 (6.31) | 191 | 12.60 (5.79) | 1.34 [.08, 2.60] | 0.238 | 0.037 |
| Upwards appearance comparison | |||||||
| Baseline | 162 | 9.27 (5.42) | 214 | 9.60 (5.52) | |||
| Post-intervention | 164 | 9.55 (5.81) | 204 | 10.22 (5.63) | 0.56 [−0.46, 1.59] | 0.102 | 0.281 |
| 6-month follow-up | 153 | 10.31 (6.02) | 178 | 9.89 (5.71) | −0.24 [−1.31, 0.83] | −0.044 | 0.664 |
| 12-month follow-up | 149 | 9.87 (5.81) | 191 | 10.18 (5.71) | 0.37 [−0.80, 1.55] | 0.068 | 0.531 |
Effects are based on multiple imputations (n = 50 imputations). Differences compare post-intervention to all other timepoints, adjusted for age, language, and school type.