Table 1.
Demographic characteristics of 1250 Chinese adolescents aged 13–21 yr
| Variables | Males | Females | Pa |
|---|---|---|---|
| n | 675 | 575 | |
| Age (yr) | 16.5 ± 2.0 | 16.7 ± 2.1 | 0.197 |
| Weight (kg) | 48.6 ± 8.1 | 46.3 ± 6.7 | <0.0001 |
| Height (cm) | 160.7 ± 7.8 | 152.5 ± 5.3 | <0.0001 |
| BMI (kg/m2) | 18.7 ± 2.2 | 19.9 ± 2.5 | <0.0001 |
| BMI Z-scoreb | −0.04 ± 0.98 | −0.04 ± 1.01 | 0.476 |
| Body composition (kg) | |||
| FM | 5.8 ± 3.5 | 12.9 ± 4.3 | <0.0001 |
| LM | 41.3 ± 6.5 | 31.6 ± 3.2 | <0.0001 |
| Adiponectin (μg/ml) | 19.0 ± 10.9 | 22.4 ± 12.5 | <0.0001 |
| ln(Adiponectin) | 2.8 ± 0.6 | 2.9 ± 0.6 | <0.0001 |
| Leptin (pg/ml) | 2059.7 ± 2421.1 | 8388.9 ± 5551.6 | <0.0001 |
| ln(Leptin) | 7.3 ± 0.7 | 8.8 ± 0.7 | <0.0001 |
| BMC (g) | |||
| WB | 1498.9 ± 350.2 | 1324.2 ± 233.6 | <0.0001 |
| Lumbar spine | 36.8 ± 9.8 | 35.6 ± 6.8 | <0.0001 |
| TH | 28.3 ± 5.7 | 23.9 ± 3.5 | <0.0001 |
| BA (cm2) | |||
| WB | 1658.3 ± 244.1 | 1521.1 ± 181.2 | <0.0001 |
| Lumbar spine | 38.9 ± 5.7 | 35.8 ± 3.9 | <0.0001 |
| TH | 31.0 ± 3.3 | 27.0 ± 2.0 | <0.0001 |
| Hip geometric indices | |||
| CSA (cm2) | 1.36 ± 0.25 | 1.17 ± 0.16 | <0.0001 |
| SM (cm3) | 0.55 ± 0.14 | 0.42 ± 0.08 | <0.0001 |
| Tanner stage | |||
| I | 60 (8.9) | 8 (1.4) | |
| II | 110 (16.3) | 91 (15.8) | |
| III | 132 (19.5) | 215 (37.4) | |
| IV | 143 (21.2) | 149 (25.9) | |
| V | 133 (19.7) | 104 (18.1) | |
| Unknown | 97 (14.4) | 8 (1.4) | <0.0001 |
| Menarche status | |||
| No | 66 (11.5) | ||
| Menarche at ≤13 yr | 214 (37.3) | ||
| Menarche at 14 yr | 150 (26.1) | ||
| Menarche at ≥15 yr | 145 (25.2) | ||
| Physical activity | |||
| Low | 209 (31.0) | 226 (39.3) | |
| Moderate | 237 (35.1) | 192 (33.4) | |
| Heavy | 158 (23.4) | 95 (16.5) | |
| Unknown | 71 (10.5) | 62 (10.8) | 0.003 |
| Student (yes) | 502 (74.4) | 374 (65.0) | 0.0003 |
| Passive smoking (yes) | 476 (72.8) | 374 (68.6) | 0.105 |
| Current smoking (yes) | 64 (9.5) | 0 | <0.0001 |
Mean ± sd is shown for continuous variables, and number (percentage) is shown for categorical variables.
a
t test and χ2 test were performed to compare gender difference in continuous variables and categorical variables, respectively.
b
Using the subset of our samples, which was composed of unrelated subjects drawn randomly from each twin pair, as the reference group.