Table 3.
Baseline characteristics of school pupils participating in the WAVES study overall and by trial arm
| Characteristics | Intervention arm | Control arm | Total |
|---|---|---|---|
| Demographic | n=662 | n=735 | n=1397 |
| Mean (SD) age (years); not known | 6.3 (0.3); 27 | 6.3 (0.3); 43 | 6.3 (0.3); 70 |
| Sex: | n=689 | n=778 | n=1467 |
| Male | 339 (49.2) | 410 (52.7) | 749 (51.1) |
| Female | 350 (50.8) | 368 (47.3) | 718 (48.9) |
| Ethnicity: | n=676 | n=775 | n=1451 |
| White British | 297 (43.9) | 361 (46.6) | 658 (45.3) |
| South Asian | 221 (32.7) | 222 (28.6) | 443 (30.5) |
| Black African-Caribbean | 62 (9.2) | 53 (6.8) | 115 (7.9) |
| Other | 96 (14.2) | 139 (17.9) | 235 (16.2) |
| Not known* | 13 | 3 | 16 |
| Deprivation fifth†: | n=670 | n=769 | n=1439 |
| 1 (most deprived) | 392 (58.5) | 398 (51.8) | 790 (54.9) |
| 2 | 120 (17.9) | 154 (20.0) | 274 (19.0) |
| 3 | 72 (10.7) | 74 (9.6) | 146 (10.1) |
| 4 | 65 (9.7) | 54 (7.0) | 119 (8.3) |
| 5 (least deprived) | 21 (3.1) | 89 (11.6) | 110 (7.6) |
| Median (interquartile range) deprivation score†; not known* | 39.8 (21.9-52.7); 19 | 37.6 (17.9-48.8); 9 | 38.9 (20.1-49.5); 28 |
| Anthropometric | |||
| BMI z score: | n=660 | n=732 | n=1392 |
| Mean (SD) BMI z score; not known | 0.23 (1.2); 29 | 0.15 (1.2); 46 | 0.19 (1.2); 75 |
| Height (cm): | n=664 | n=732 | n=1396 |
| Mean (SD); not known: | 118.6 (5.6); 25 | 118.2 (5.4); 46 | 118.4 (5.5); 71 |
| Waist circumference, z score: | n=589 | n=670 | n=1259 |
| Mean (SD); not known: | 0.77 (1.2); 100 | 0.66 (1.3); 108 | 0.71 (1.3); 208 |
| Sum of skinfolds (mm)‡ | n=540 | n=597 | n=1137 |
| Median (interquartile range); not known | 28.6 (23.3-35.4); 149 | 28.1 (23.0-36.6); 181 | 28.4 (23.1-36.1); 330 |
| Body fat %: | n=660 | n=716 | n=1376 |
| Mean (SD); not known | 21.3 (5.4); 29 | 21.0 (5.2); 62 | 21.1 (5.3); 91 |
| Weight status§: | n=660 | n=732 | n=1392 |
| Underweight (≤2nd centile) | 20 (3.0) | 20 (2.7) | 40 (2.9) |
| Healthy weight (>2nd and <85th centiles) | 495 (75.0) | 562 (76.8) | 1057 (75.9) |
| Overweight (≥85th and <95th centiles) | 61 (9.2) | 63 (8.6) | 124 (8.9) |
| Obese (≥95th centile) | 84 (12.7) | 87 (11.9) | 171 (12.3) |
| Not known* | 29 | 46 | 75 |
| 24 hour dietary intake | n=562 | n=625 | n=1187 |
| Median (interquartile range) energy (kJ/24 hrs); not known | 6904 (5865-8054); 127 | 6911 (5804-7964); 153 | 6907 (5829-8002); 280 |
| ≥5 portions of fruit and vegetables: | n=562 | n=625 | n=1187 |
| Yes | 336 (59.8) | 405 (64.8) | 741 (62.4) |
| No | 226 (40.2) | 220 (35.2) | 446 (37.6) |
| Not known* | 127 | 153 | 280 |
| Physical activity | n=492 | n=560 | n=1052 |
| Mean (SD) physical activity energy expenditure (kJ/kg/day); not known | 96.4 (23.2); 197 | 94.1 (24.4); 218 | 95.2 (23.8); 415 |
| ≥60 mins MVPA/24 hours: | n=491 | n=557 | n=1048 |
| Yes | 228 (46.4) | 276 (49.6) | 504 (48.1) |
| No | 263 (53.6) | 281 (50.4) | 544 (51.9) |
| Not known* | 198 | 221 | 419 |
| Psychological | n=663 | n=721 | n=1384 |
| Median (interquartile ranage) PedsQL total score; not known | 71.7 (60.9-82.6); 26 | 73.9 (60.9-82.6); 57 | 71.7 (60.9-82.6); 83 |
MVPA=moderate to vigorous physical activity; PedsQL=pediatric quality of life inventory.
*
Not included in denominator for calculation of percentages.
†
Index of multiple deprivation.
‡
Subscapular, suprailiac, biceps, and triceps skinfolds.
§
Based on UK 1990 reference centile curves and applying cut-offs used for population monitoring.