Table 1.
Summary characteristics of the sample by survey year
| Survey year | ||||
|---|---|---|---|---|
| 1997 | 2004 | 2010 | 2015 | |
| Child response rates (%) | 87 | 66 | 57 | 63 |
| Sample size | 5518 | 5407 | 8058 | 7555 |
| Available BMI data (n) | 5402 | 5395 | 7734 | 7374 |
| Available WHtR data (n) | 4391 | 5399 | 7850 | 7354 |
| Girls (%) | 46.5 | 48.9 | 48.0 | 51.5 |
| Age years, (mean, SD) | 11.2 (2.8) | 10.5 (3.4) | 10.6 (3.4) | 10.3 (3.3) |
| Socioeconomic status (%) | ||||
| Low | 32.8 | 28.1 | 25.9 | 24.5 |
| Middle | 33.5 | 34.8 | 41.3 | 34.4 |
| High | 33.8 | 37.1 | 32.7 | 41.1 |
BMI body mass index, WHtR waist-to-height ratio, n/a data not available
1997 survey: 1996 Census; 2004 survey: 2006 Census; 2010 survey: 2011 Census; and 2015 survey: 2016 Census.