Demographic characteristics of Korean school-aged children and adolescents from 2008 to 2011 according to the Korea National Health and Nutrition Examination Survey (KNHANES)
| KNHANES IV | KNHANES V | p Value | |||
| 2008 n*=902 n†=4 715 528 | 2009‡ n*=617 n†=2 896 674 | 2010 n*=340N†=5 227 550 | 2011 n*=338N†=5 679 730 | ||
| Age group (years) | |||||
| 10–12 | 36.3 (32.8 to 39.7) | 31.6 (27.8 to 35.3) | 28.9 (22.8 to 35.0) | 28.7 (22.2 to 35.2) | |
| 13–15 | 29.7 (26.5 to 32.9) | 35.2 (31.5 to 38.8) | 38.1 (31.7 to 44.4) | 34.4 (28.8 to 40.0) | |
| 16–18 | 34.0 (30.6 to 37.4) | 33.3 (29.5 to 37.1) | 33.0 (26.1 to 40.0) | 36.9 (30.2 to 43.6) | 0.217 |
| Sex, male | 57.2 (53.6 to 60.9) | 58.0 (53.3 to 62.7) | 55.2 (50.8 to 59.7) | 56.8 (52.3 to 61.4) | 0.850 |
| Residence area | |||||
| Seoul | 21.8 (17.0 to 26.5) | 25.0 (16.0 to 34.0) | 15.2 (11.6 to 18.8) | 22.1 (17.1 to 27.2) | |
| Other cities | 61.4 (53.8 to 69.1) | 61.2 (50.9 to 71.6) | 65.0 (56.1 to 73.9) | 62.2 (53.6 to 70.7) | |
| Rural area | 16.8 (10.1 to 23.5) | 13.8 (6.7 to 20.9) | 19.8 (11.0 to 28.5) | 15.7 (8.2 to 23.3) | 0.700 |
| Monthly household income§ | |||||
| Low (<120%) | 25.1 (20.7 to 29.5) | 19.3 (14.1 to 24.5) | 19.3 (13.1 to 25.5) | 16.7 (11.1 to 22.2) | |
| Middle (120–250%) | 40.4 (35.6 to 45.2) | 37.9 (31.7 to 44.1) | 38.7 (31.9 to 45.4) | 37.0 (30.3 to 43.7) | |
| High (≥250%) | 34.5 (29.2 to 39.8) | 42.8 (36.1 to 49.6) | 42.1 (34.6 to 49.5) | 46.3 (39.4 to 53.2) | 0.187 |
Data are presented as proportion (95% CI).
*Participants in the KNHANES IV, V.
†Estimated Korean population weighted by year.
‡The subjects in 2009 represent half of the whole student sample; for an administrative reason, the survey was conducted in the second half of the year.
§Calculated based on the minimum cost of living (MCL) measured by the government. MCL reflects family size and inflation each year.