Characteristics of the study population
| Vitamin D level | |||||
| Total (n=2515) | Deficiency (<20 ng/mL) | Insufficiency (≥20 to <30 ng/mL) | Sufficiency (≥30 ng/mL) | p Value | |
| Age | 14.39±0.07 | 14.66±0.08 | 13.46±0.15 | 14.07±0.52 | <0.0001 |
| Sex | |||||
| Male | 1314 (53.39) | 914 (51.20) | 359 (59.74) | 41 (71.46) | 0.0031 |
| Female | 1201 (46.61) | 929 (37.45) | 254 (40.26) | 18 (28.54) | |
| Region of residence | |||||
| Urban | 1709 (71.98) | 1297 (73.59) | 379 (67.94) | 33 (50.84) | 0.0108 |
| Rural | 806 (28.02) | 546 (26.41) | 234 (32.06) | 26 (49.16) | |
| Regular exercise | |||||
| No | 1861 (73.83) | 1375 (74.94) | 449 (70.20) | 37 (69.98) | 0.1912 |
| Yes | 654 (26.17) | 468 (25.06) | 164 (29.80) | 22 (30.02) | |
| Regular walking | |||||
| No | 1354 (53.23) | 981 (52.98) | 339 (54.37) | 34 (50.44) | 0.8708 |
| Yes | 1161 (46.77) | 862 (47.02) | 274 (45.63) | 25 (49.56) | |
| Income | |||||
| Lowest | 306 (13.87) | 229 (14.33) | 71 (12.78) | 6 (6.83) | 0.0996 |
| Lower middle | 604 (27.04) | 452 (27.66) | 133 (24.41) | 19 (31.94) | |
| Higher middle | 803 (30.39) | 580 (30.92) | 210 (29.54) | 13 (17.44) | |
| Highest | 802 (28.71) | 582 (27.09) | 199 (33.27) | 21 (43.79) | |
| Season | |||||
| April–October | 1465 (58.38) | 930 (51.36) | 485 (81.49) | 50 (82.62) | <0.0001 |
| November–March | 1050 (41.62) | 913 (48.64) | 128 (18.51) | 9 (17.38) | |
| BMI | 20.88±0.10 | 21.12±0.13 | 20.08±0.19 | 20.12±0.47 | <0.0001 |
| Smoking | |||||
| Active | 382 (18.22) | 293 (19.08) | 75 (13.99) | 14 (32.22) | 0.0075 |
| Passive | 1200 (43.39) | 913 (44.36) | 261 (39.98) | 26 (42.56) | |
| No | 933 (38.40) | 637 (36.56) | 277 (46.03) | 19 (25.22) | |
| Atopic dermatitis | |||||
| No | 2247 (89.44) | 1648 (88.99) | 546 (90.83) | 53 (92.28) | 0.4675 |
| Yes | 268 (10.56) | 195 (11.01) | 67 (9.17) | 6 (7.72) | |
| Asthma | |||||
| No | 2412 (95.87) | 1771 (95.85) | 583 (95.68) | 58 (99.26) | 0.5376 |
| Yes | 103 (4.13) | 72 (4.15) | 30 (4.32) | 1 (0.74) | |
Univariate and multivariate analyses of factors associated with serum 25(OH)D.
Data are presented as mean±SE, n (weighted %).
Statistics were carried out using Rao-Scott χ2 test.
25OHD, 25-hydroxyvitamin D; BMI, body mass index.