Background
Methods
Context
Consent procedures
Participants
Measures
BMI calculation and categorization
Household composition
Family composition
Number of siblings
Adolescent SES
School SEC
Diet
School lunch
PA and its related metabolic equivalent task (MET)
Active transportation
Sport participation
PA proxy measure
Analysis
Results
Variables | All | School SEC | ||
---|---|---|---|---|
Low (n = 3) | Medium (n = 5) | High (n = 3) | ||
Age (M, SD) | 15.92 (1.33) | 16.61 (1.16) | 15.37 (1.24) | 15.82 (1.26) |
Sex (n, %) | ||||
Boys | 515 (49.6%) | 186 (53.6%) | 195 (51.6%) | 142 (45.4%) |
Girls | 523 (50.4%) | 161 (46.4%) | 183 (48.4%) | 171 (54.6%) |
Body Mass Index | ||||
Weight / Height (M, SD) | 20.83 (3.32) | 21.97 (3.8) | 20.59 (3.09) | 19.85 (2.57) |
CDC Z-Scores (M, SD) | −0.09 (1.01) | 0.11 (1.05) | −0.04 (0.97) | −0.37 (0.94) |
Underweight | 65 (6.3%) | 16 (4.6%) | 22 (5.8%) | 27 (8.6%) |
Normal Weight | 846 (81.5%) | 274 (79.0%) | 308 (81.5%) | 264 (84.3%) |
Overweight | 92 (8.9%) | 38 (11.0%) | 36 (9.5%) | 18 (5.8%) |
Obesity | 35 (3.4%) | 19 (5.5%) | 12 (3.2%) | 4 (1.3%) |
Overweight|Obesity | 127 (12.2%) | 57 (16.4%) | 48 (12.7%) | 22 (7.0%) |
Physical Activity | ||||
Low | 282 (27.2%) | 142 (40.9%) | 79 (20.9%) | 61 (19.5%) |
Medium | 623 (60.0%) | 162 (46.7%) | 245 (64.8%) | 216 (69.0%) |
High | 133 (12.8%) | 43 (12.4%) | 54 (14.3%) | 36 (11.5%) |
Adolescent SES | ||||
Low | 351 (33.8%) | 214 (61.7%) | 108 (28.6%) | 29 (9.3%) |
Medium | 277 (26.7%) | 63 (18.2%) | 118 (31.2%) | 96 (30.7%) |
High | 368 (35.5%) | 50 (14.4%) | 137 (36.2%) | 181 (57.8%) |
NA | 42 (4.1%) | 20 (5.8%) | 15 (4.0%) | 7 (2.2%) |
School Lunch (n, %) | ||||
Lunch outside school | 490 (47.2%) | 304 (87.6%) | 189 (50.0%) | 55 (17.6%) |
Lunch at school | 548 (52.8%) | 43 (12.4%) | 189 (50.0%) | 258 (82.4%) |
Household Composition | ||||
Live with both parents | 680 (65.5%) | 218 (62.8%) | 231 (61.1%) | 231 (73.8%) |
Do not live with both parents | 358 (34.5%) | 129 (37.2%) | 147 (38.9%) | 82 (26.2%) |
Number of Siblings (M, SD) | 2.13 (1.55) | 2.9 (1.76) | 1.92 (1.45) | 1.54 (0.98) |
Overall | 1038 (100.0%) | 347 (100.0%) | 378 (100.0%) | 313 (100.0%) |
School lunch and physical activity levels by school SEC
Overweight|obesity risk
Variables | Univariable Analysis | Full Model without interaction with BCa | Full Model with interaction and BCa | Stepwise Model with BCa |
---|---|---|---|---|
Age | 0.89 [0.77;1.02] | 0.80** [0.68;0.95] | 0.81* [0.70;0.97] | 0.81* [0.69;0.98] |
Sex | ||||
Girls (ref.) | ||||
Boys | 1.29 [0.89;1.87] | 1.53* [1.03;2.29] | 1.54* [1.01;2.34] | 1.53 [1.00;2.35] |
Adolescent SES | ||||
Low (ref.) | ||||
Medium | 0.76 [0.47;1.21] | 0.97 [0.58;1.62] | 1.78 [0.83;3.91] | 1.78 [0.71;3.51] |
High | 0.59* [0.37;0.93] | 0.94 [0.55;1.59] | 2.37 [1.00;5.52] | 2.38 [0.99;5.54] |
School SEC | ||||
Low (ref.) | ||||
Medium | 0.74 [0.49;1.12] | 0.58 [0.33;1.01] | 1.11 [0.54;2.32] | 1.15 [0.56;2.28] |
High | 0.38*** [0.22;0.64] | 0.34** [0.17;0.68] | 1.14 [0.31;3.52] | 1.24 [0.27;3.29] |
School Lunch | ||||
Outside of school (ref.) | ||||
At school | 0.70 [0.47;1.01] | 1.08 [0.66;1.76] | 1.16 [0.69;1.91] | – |
Physical Activity | ||||
Low PA (ref.) | ||||
Medium PA | 0.82 [0.55;1.24] | 1.01 [0.65;1.6] | 1.03 [0.65;1.65] | 1.02 [0.64;1.65] |
High PA | 0.48* [0.22;0.95] | 0.44* [0.19;0.93] | 0.42* [0.18;0.95] | 0.41* [0.17;0.90] |
Household Composition | ||||
Live with both parents (ref.) | ||||
Do not live with both parents | 1.13 [0.77;1.66] | 1.01 [0.66;1.52] | 1.01 [0.65;1.58] | – |
Number of Siblings (M, SD) | 1.14* [1.02;1.27] | 1.10 [0.97;1.25] | 1.12 [0.98;1.28] | 1.11 [0.97;1.26] |
Adolescent SES x School SEC | ||||
Low Adolescent SES x Low School SEC | ref. | ref. | ||
Medium Adolescent SES x Medium School SEC | 0.43 [0.15;1.30] | 0.43 [0.15;1.36] | ||
High Adolescent SES x Medium School SEC | 0.15** [0.05;0.56] | 0.16** [0.04;0.50] | ||
Medium Adolescent SES x High-School SEC | 0.08* [0.00;0.62] | 0.08* [0.00;0.70] | ||
High Adolescent SES x High-School SEC | 0.18* [0.04;0.89] | 0.18* [0.04;0.82] | ||
Aikake Information Criterion | 729 | 718.52 | 714.9 | |
Sensitivity | 73.6% | 79.3% | 79.3% | |
Specificity | 50.9% | 50.1% | 50.9% | |
Area Under Curve | 0.653 | 0.691 | 0.690 |
Models comparison
Main effects
Interaction effects analysis
Within School | Adolescent-SES Contrasts | Odds-Ratio |
Low-SEC | Low-Medium | 0.56 [0.26;1.21] |
Medium-High | 0.75 [0.27;1.92] | |
Low-High | 0.42 [0.19;1.04] | |
Medium-SEC | Low-Medium | 1.32 [0.63;2.84] |
Medium-High | 2.11 [0.85;5.29] | |
Low-High | 2.79* [1.22;7.41] | |
High-SEC | Low-Medium | 6.86* [1.06;5.22*106] |
Medium-High | 0.35 [0.00;1.63] | |
Low-High | 2.39 [0.55;7.85] | |
Within SES | School SEC Contrasts | Odds-Ratio |
Low SES | Low-Medium | 0.90 [0.44;1.79] |
Medium-High | 0.98 [0.33;3.99] | |
Low-High | 0.88 [0.29;3.55] | |
Medium SES | Low-Medium | 2.12 [0.80;5.47] |
Medium-High | 5.08** [1.55;24.84] | |
Low-High | 10.75** [2.67;64.57] | |
High SES | Low-Medium | 5.94** [1.94;17.29] |
Medium-High | 0.84 [0.32;2.20] | |
Low-High | 4.99** [1.71;13.14] |
Variables | School SEC | ||||||
---|---|---|---|---|---|---|---|
Low | Medium | High | |||||
Observed | Predicted | Observed | Predicted | Observed | Predicted | ||
Adolescent SES | Low | 29 (13.6%) | 24 (11.4%) | 19 (17.6%) | 14 (12.9%) | 5 (17.2%) | 4 (13.7%) |
Medium | 13 (20.6%) | 12 (18.6%) | 17 (14.4%) | 12 (10.2%) | 3 (3.1%) | 2 (2.3%) | |
High | 12 (24.0%) | 12 (23.4%) | 9 (6.6%) | 7 (5.2%) | 14 (7.7%) | 11 (6.3%) |