Table 2.
Characteristics of the group at each time point including allocation of time use
| Variable | Category | Age (years) | |||
|---|---|---|---|---|---|
| 1 | 2 | 3.5 | 5 | ||
| n | 355 | 213 | 231 | 248 | |
| Female n (%) | 172 (48.5) | 93 (43.7) | 107 (46.3) | 122 (49.2) | |
| Age (months) | 12.2 (0.3) | 24.1 (0.2) | 41.9 (0.5) | 59.7 (0.4) | |
| Height (cm) | 75.6 (2.8) | 86.2 (3.1) | 99.1 (3.8) | 109.9 (4.4) | |
| Weight (kg) | 9.8 (1.1) | 12.5 (1.4) | 16.0 (1.8) | 19.4 (2.4) | |
| BMI (kg/m2) | 17.2 (1.3) | 16.8 (1.3) | 16.3 (1.2) | 16.0 (1.2) | |
| BMI z-score | 0.39 (0.83) | 0.70 (0.89) | 0.61 (0.83) | 0.47 (0.81) | |
| Weight statusa n (%) | Normal weight | 281 (79.2) | 140 (65.7) | 158 (68.4) | 190 (76.6) |
| Overweight | 52 (14.7) | 43 (20.2) | 45 (19.5) | 40 (16.1) | |
| Obese | 22 (6.2) | 30 (14.1) | 28 (12.1) | 18 (7.3) | |
| Sleep componentsb | Night-time sleep | 578 (55) | 594 (60) | 626 (44) | 632 (39) |
| (minutes) | Wake after sleep onset | 29 (27) | 20 (22) | 15 (16) | 12 (14) |
| Day time naps | 121 (43) | 89 (42) | 23 (26) | -c | |
| Activity componentsb | Sedentary | 524 (58) | 443 (61) | 462 (54) | 476 (58) |
| (minutes) | LPA | 184 (64) | 284 (56) | 292 (54) | 287 (54) |
| MVPA | 4 (6) | 10 (8) | 22 (14) | 33 (17) | |
Data presented as mean (SD) except for weight status which is n (%) and only includes those with valid accelerometry data
LPA is light physical activity, MVPA is moderate-to-vigorous physical activity
aNormal weight defined as BMI < 85th, overweight as a BMI z-score ≥ 85th but <95th percentile, and obesity as BMI ≥ 95th percentile according to the WHO growth standards [25]
bData presented as arithmetic mean (SD) which is the average number of minutes spent in each category after individualised normalisation to 24 h
cCould not be calculated as no children napped at this age