Table 1. Characteristics of participants according to sex.
| Variables | Total | Male | Female | P |
|---|---|---|---|---|
| No. of participants | 982 | 508 | 474 | - |
| Age, yr | 15.6 ± 0.1 | 15.5 ± 0.1 | 15.7 ± 0.1 | 0.249 |
| Height Z-score | 0.2 ± 0.1 | 0.7 ± 0.1 | 0.3 ± 0.1 | < 0.001 |
| BMI Z-score | 0.1 ± 0.1 | 0.1 ± 0.1 | 0.1 ± 0.1 | 0.825 |
| HOMA-IR | 2.8 ± 0.1 | 2.8 ± 0.1 | 2.7 ± 0.1 | 0.451 |
| Vitamin D deficiency | 758 (77.9) | 380 (76.1) | 378 (79.9) | 0.217 |
| Sufficient calcium intake | 102 (10.4) | 68 (14.3) | 34 (6.0) | < 0.001 |
| Regular physical activity | 123 (11.7) | 92 (17.0) | 31 (5.8) | < 0.001 |
| FM Z-score, g | 0.16 ± 0.05 | 0.10 ± 0.07 | 0.23 ± 0.08 | 0.204 |
| LM Z-score, g | 0.19 ± 0.06 | 0.17 ± 0.07 | 0.21 ± 0.07 | 0.635 |
| Total body less head BMC Z-score, g | 0.11 ± 0.06 | 0.17 ± 0.07 | 0.13 ± 0.08 | 0.602 |
| Lumbar spine BMC Z-score, g | 0.11 ± 0.06 | 0.14 ± 0.07 | 0.08 ± 0.07 | 0.431 |
| Femur neck BMC Z-score, g | 0.09 ± 0.05 | 0.09 ± 0.06 | 0.10 ± 0.07 | 0.879 |
| Total body less head BMD Z-score, g/cm2 | −0.05 ± 0.07 | 0.03 ± 0.07 | −0.04 ± 0.08 | 0.365 |
| Lumbar spine BMD Z-score, g/cm2 | 0.03 ± 0.05 | 0.07 ± 0.06 | −0.02 ± 0.07 | 0.191 |
| Femur neck BMD Z-score, g/cm2 | 0.06 ± 0.04 | 0.04 ± 0.05 | 0.08 ± 0.06 | 0.604 |
| Lumbar spine BMAD Z-score, g/cm3 | −0.03 ± 0.05 | 0.01 ± 0.05 | −0.07 ± 0.07 | 0.255 |
| Femur neck BMAD Z-score, g/cm3 | 0.00 ± 0.04 | −0.03 ± 0.05 | 0.04 ± 0.06 | 0.361 |
Data are expressed as the mean ± standard error or number (%).
BMI = body mass index, HOMA-IR = homeostasis model assessment-insulin resistance, FM = fat mass, LM = lean mass, BMC = bone mineral content, BMD = bone mineral density, BMAD = bone mineral apparent density.