Table 1.
Characteristics of study participants according to sex and 25(OH)D levels according to subgroups; adolescents aged 10–19 years, Korea National Health and Nutrition Examination Survey (KNHANES) 2009–2010
| Total | Males | Females | 25(OH)D (nmol/l) | ||||
|---|---|---|---|---|---|---|---|
| n | % | n | n | Mean | se | P value* | |
| Total participants | 1466 | 100 | 769 | 697 | 42·6 | 0·6 | |
| Age (years) | |||||||
| 10–14 | 804 | 54·8 | 431 | 373 | 44·8 | 0·7 | <0·001 |
| 15–19 | 662 | 45·2 | 338 | 324 | 39·6 | 0·8 | |
| Sex | |||||||
| Males | 769 | 52·5 | 769 | 0 | 42·8 | 0·7 | 0·021 |
| Females | 697 | 47·5 | 0 | 697 | 41·0 | 0·7 | |
| Season | |||||||
| Spring | 206 | 14·1 | 111 | 95 | 37·4 | 1·0 | <0·01† |
| Summer | 435 | 29·7 | 230 | 205 | 47·7 | 0·9 | |
| Autumn | 438 | 29·8 | 229 | 209 | 44·3 | 0·8 | |
| Winter | 387 | 26·4 | 199 | 188 | 35·6 | 0·7 | |
| Degree of obesity | |||||||
| Lean | 1158 | 79·0 | 598 | 560 | 41·9 | 0·6 | 0·25‡ |
| Overweight | 189 | 12·9 | 104 | 85 | 43·1 | 1·1 | |
| Obese | 119 | 8·1 | 67 | 52 | 40·8 | 1·7 | |
| WC ≥90th percentile | |||||||
| Yes | 126 | 8·6 | 61 | 65 | 41·0 | 1·7 | 0·53 |
| No | 1340 | 91·4 | 708 | 632 | 42·1 | 0·6 | |
| Regular PA | |||||||
| Yes | 951 | 63·9 | 565 | 386 | 43·6 | 0·7 | <0·001 |
| No | 515 | 36.1 | 204 | 311 | 39·1 | 0·7 | |
| IFG | |||||||
| Yes | 61 | 4·2 | 31 | 30 | 40·5 | 1·9 | 0·43 |
| Lean | 32 | 14 | 18 | 40·7 | 1·4 | 0·93 | |
| Overweight or obese | 29 | 17 | 12 | 40·4 | 3·3 | ||
| No | 1405 | 95·8 | 738 | 667 | 42·0 | 0·6 | |
| HOMA-IR | 1466 | 769 | 697 | 2·92 | 0·05 | ||
| QUICKI | 1466 | 769 | 697 | 0·33 | 0·00 | ||
25(OH)D, 25-hydroxyvitamin D; WC, waist circumference; PA, physical activity; IFG, impaired fasting glucose; HOMA-IR, homeostatic model assessment–insulin resistance index; QUICKI, quantitative insulin-sensitivity check index.
*Mean 25(OH)D concentrations according to subgroups were compared with an independent-samples t test.
†Each mean 25(OH)D concentration according to subgroup was compared with the mean for the summer subgroup with an independent-samples t test.
‡A pairwise comparison was performed between all subgroups.