Table 2. Characteristics according to the BMI groups (underweight, normal-weight, and overweight/obesity).
| Variables | Male (n = 508) | Female (n = 474) | ||||||
|---|---|---|---|---|---|---|---|---|
| Underweight | Normal-weight | Overweight/obesity | P for trend | Underweight | Normal-weight | Overweight/obesity | P for trend | |
| No. of participants | 77 | 323 | 108 | - | 69 | 304 | 101 | - |
| Age, yr | 15.8 ± 0.3 | 15.5 ± 0.2 | 15.5 ± 0.3 | 0.685 | 16.4 ± 0.3* | 15.6 ± 0.2 | 15.6 ± 0.3‡ | 0.041 |
| Height Z-score | 0.4 ± 0.1 | 0.7 ± 0.1† | 1.0 ± 0.1‡ | 0.001 | 0.3 ± 0.2 | 0.3 ± 0.1 | 0.4 ± 0.1 | 0.962 |
| BMI Z-score | −1.6 ± 0.1* | 0.0 ± 0.0† | 1.5 ± 0.0‡ | < 0.001 | −1.6 ± 0.1* | −0.1 ± 0.0† | 1.7 ± 0.1‡ | < 0.001 |
| HOMA-IR | 2.1 ± 0.1* | 2.6 ± 0.1† | 4.2 ± 0.2‡ | < 0.001 | 2.2 ± 0.1* | 2.6 ± 0.1† | 3.5 ± 0.2‡ | < 0.001 |
| 25-hydroxyvitamin D, ng/mL | 6.8 ± 0.3 | 6.7 ± 0.1 | 6.6 ± 0.2 | 0.865 | 7.3 ± 0.4* | 6.3 ± 0.2 | 6.2 ± 0.3‡ | 0.031 |
| Vitamin D deficiency | 59 (76.9) | 237 (76.7) | 84 (73.7) | 0.885 | 47 (67.5) | 244 (80.0) | 87 (87.9)‡ | 0.006 |
| Calcium intake, mg/day | 595.4 ± 57.2 | 552.8 ± 25.2 | 584.4 ± 36.0 | 0.402 | 431.7 ± 26.2 | 423.8 ± 21.6 | 418.2 ± 22.1 | 0.438 |
| Sufficient calcium intake | 10 (17.9) | 43 (12.9) | 15 (15.9) | 0.630 | 4 (4.2) | 24 (5.8) | 6 (8.2) | 0.612 |
| Physical activity, hours/week | 7.0 ± 1.2 | 7.8 ± 1.2 | 8.5 ± 1.1 | 0.961 | 2.8 ± 1.2 | 4.6 ± 0.7 | 6.0 ± 1.4 | 0.636 |
| Regular physical activity | 11 (20.4) | 59 (16.5) | 22 (15.8) | 0.822 | 0 (0)* | 20 (6.0) | 11 (9.3)‡ | < 0.001 |
Data are expressed as the mean ± standard error or number (%).
BMI = body mass index, HOMA-IR = homeostasis model assessment-insulin resistance.
*P < 0.05 between underweight and normal-weight groups. † P < 0.05 between normal-weight and overweight/obese groups. ‡ P < 0.05 between underweight and overweight/obese groups.