Table 1.
Descriptive characteristics of the SPEEDY sample, stratified by sex
| Overall | Boys | Girls | p-value | |
|---|---|---|---|---|
| Sex n (%) |
1513 |
678 (44.8) |
835 (55.2) |
|
| Age, mean ± SD, y |
10.3 ± 0.3 |
10.2 ± 0.3 |
10.3 ± 0.3 |
0.29 |
| BMI z-score, mean ± SD |
0.38 ± 1.14 |
0.42 ± 1.11 |
0.36 ± 1.16 |
0.34 |
|
Socioeconomic indicators | ||||
| - Own car, % |
95.8 |
95.2 |
96.4 |
0.24 |
| - Own/buying home, % |
75.3 |
75.4 |
75.3 |
0.96 |
| - Mother left full-time education at >16 y, % |
53.0 |
53.0 |
53.0 |
0.78 |
| - Composite SES, % |
|
|
|
0.97 |
| Lowest (score: 0 or 1) |
17.4 |
17.5 |
17.3 |
|
| Middle (score: 2) |
38.3 |
38.0 |
38.6 |
|
| Highest (score: 3) |
44.3 |
44.5 |
44.1 |
|
| Home location, % urban |
66.1 |
63.8 |
67.8 |
0.10 |
|
Accelerometer-derived data (all: mean ± SD) | ||||
| - Leisure-time sedentary time (min/wk) |
2091.3 ± 320.8 |
2070.4 ± 335.5 |
2108.3 ± 307.4 |
0.02 |
| - Valid leisure-time registered time (min/wk) |
3364.1 ± 375.7 |
3393.5 ± 385.0 |
3340.2 ± 366.5 |
0.01 |
| - Proportion of registered time spent sedentary (%) | 62.2 ± 6.5 | 61.0 ± 6.8 | 63.1 ± 6.0 | <0.001 |
The reported p-value is for sex differences.
Abbreviations: SD standard deviation, y year, min/wk minutes per week, SES socioeconomic status, BMI body mass index.