Demographic and anthropometric characteristics of children aged 8–17 years old from 1997 to 2016
| Trying to lose weight | Not trying to lose weight | |||
| n | Mean±SD/% | n | Mean±SD/% | |
| Age (years) | 8661 | 12.4±2.47 | 25 574 | 11.5±2.52* |
| Age group | ||||
| 8–12 | 5330 | 60.5 | 18 371 | 70.7* |
| 13–17 | 3331 | 39.5 | 7203 | 29.3* |
| Weight (kg) | 8661 | 53.0±22.0 | 25 574 | 40.8±16.8* |
| BMI z-score | 6446 | 2.56±1.47 | 23 604 | 1.03±1.62* |
| BMI category | ||||
| Thinness | 6 | 0.1 | 482 | 2.2* |
| Normal | 1023 | 17.4 | 11 804 | 51.5* |
| Overweight | 1231 | 19.7 | 4714 | 19.8 |
| Obesity | 4206 | 62.8 | 6604 | 26.6* |
| Gender | ||||
| Boys | 3440 | 40.4 | 13 628 | 53.9* |
| Girls | 5221 | 59.6 | 11 946 | 46.1* |
| Ethnicity | ||||
| White | 7053 | 79.1 | 22 074 | 84.8* |
| Asian | 810 | 10.9 | 1658 | 7.5* |
| Black | 394 | 5.2 | 806 | 3.5* |
| Other and mixed | 404 | 4.9 | 1036 | 4.3 |
| Household income level | ||||
| Q1 | 1875 | 27.5 | 4954 | 24.1* |
| Q2 | 1586 | 21.5 | 4442 | 20.2 |
| Q3 | 1557 | 20.9 | 4677 | 20.9 |
| Q4 | 1313 | 17.1 | 4375 | 19.1* |
| Q5 | 988 | 13.1 | 3540 | 15.6* |
Estimates are mean±SD or % in which % are added up vertically; BAZ, BMI for age z-score; Q1 (<=GBP11 676.65), Q2 (>GBP11 676.65<=GBP19 117.65), Q3 (>GBP19 117.65<=GBP27 704.92), Q4 (>GBP27 704.92<=GBP47 794.12) and Q5 (>GBP47 794.12). Children ‘Not-trying to lose weight’ include those ‘trying to gain weight (n=1,456 (4.2%))’. Missing values; BAZ classfications 16.8%, household income level 15.6%.
*Significant different (p<0.05) between groups (χ2 and t-test).
BAZ, body mass index for age z-score ; BMI, body mass index .