Table 1.
Characteristics of study participants by sex (Japan, 2001–2008)
| Boys (N = 1211) | Girls (N = 1139) | P valuea | |
|---|---|---|---|
| Age (years) | 12.0 (12.0, 13.0) | 12.0 (12.0, 13.0) | 0.822 |
| Bitrhweight (g), n (%) | |||
| < 2500 | 77 (6.4) | 85 (7.5) | 0.291 |
| ≥ 2500 | 1134 (93.6) | 1054 (92.5) | |
| Height (cm) | 155.6 (149.2, 161.0) | 153.3 (149.4, 157.2) | <0.001 |
| Weight (kg) | 44.3 (38.8, 50.8) | 43.5 (38.9, 48.1) | 0.007 |
| BMI (kg/m2) | 18.2 (16.8, 20.0) | 18.3 (16.9, 20.0) | 0.389 |
| BMI-SDS | 0.25(−0.35, 0.89) | 0.15 (−0.44, 0.75) | 0.002 |
| Physique, n (%) | |||
| Underweight | 99 (8.2) | 127 (11.2) | 0.005 |
| Normal weight | 933 (77.0) | 882 (77.4) | |
| Overweight/obesity | 179 (14.8) | 130 (11.4) | |
| Exercise, n (%) | |||
| Daily | 1003 (82.8) | 668 (58.7) | <0.001 |
| Sometimes | 94 (7.8) | 157 (13.8) | |
| None | 114 (9.4) | 314 (27.6) | |
| Skipping breakfast, n (%) | |||
| Yes | 58 (4.8) | 84 (7.4) | 0.009 |
| No | 1153 (95.2) | 1055 (92.6) | |
| Snacking after dinner, n (%) | |||
| Always or often | 735 (60.7) | 659 (57.9) | 0.162 |
| Seldom or none | 476 (39.3) | 480 (42.1) | 0.015 |
| Snacking while watching television or reading books, n (%) | |||
| Yes | 482 (39.8) | 510 (44.8) | 0.015 |
| No | 729 (60.2) | 629 (55.2) | |
| Eating slowly, n (%) | |||
| Yes | 207 (17.1) | 279 (24.5) | <0.001 |
| No | 1004 (82.9) | 860 (75.5) | |
BMI body mass index, BMI-SDS body mass index standard deviation score
Except where indicated n (%), values are expressed as median (25, 75th percentile)
aWilcoxon rank-sum test or chi-square test