Smoking prevalence rates of Korean school-aged children and adolescents from 2008 to 2011
| KNHANES IV | KNHANES V | ||||
| 2008 n*=902N†=4 715 528 | 2009‡ n*=617 n†=2 896 674 | 2010 n*=340 n†=5 227 550 | 2011 n*=338 n†=5 679 730 | p Value§ | |
| Current smoking | |||||
| Self-reported smoker with cotinine >100 ng/mL | 6.7 (4.5 to 8.8) | 5.6 (2.9 to 8.3) | 1.9 (0.2 to 3.6) | 9.0 (4.9 to 13.1) | |
| Self-reported smoker with cotinine ≤100 ng/mL | 1.1 (0.2 to 2.0) | 1.6 (0.4 to 2.8) | 2.1 (0.0 to 4.3) | 0.7 (0.0 to 1.5) | |
| Self-reported non-smoker with cotinine >100 ng/mL | 4.8 (2.8 to 6.7) | 2.4 (1.0 to 3.8) | 4.2 (1.5 to 6.9) | 6.1 (2.6 to 9.5) | |
| Missing self-report with cotinine >100 ng/mL | 0 | 0 | 0 | 0 | |
| Subtotal | 12.6 (9.6 to 15.5) | 10.0 (6.8 to 13.2) | 8.1 (4.6 to 11.7) | 15.7 (10.5 to 20.9) | |
| Non smoking | |||||
| Self-reported non-smoker with cotinine ≤100 ng/mL | 65.7 (61.4 to 70.1) | 70.9 (66.1 to 75.7) | 85.3 (80.5 to 90.0) | 80.7 (75.1 to 86.3) | |
| Missing self-report with cotinine ≤100 ng/mL | 0.4 (0.0 to 0.9) | 0 | 0.2 (0.0 to 0.7) | 0 | |
| Undetectable cotinine¶ | 21.3 (17.4 to 25.2) | 19.1 (14.9 to 23.3) | 6.3 (2.7 to 9.9) | 3.5 (1.3 to 5.8) | |
| Subtotal | 87.4 (84.4 to 90.4) | 90.0 (86.8 to 93.2) | 91.9 (88.3 to 95.4) | 84.3 (79.1 to 89.5) | 0.018 |
Data are presented as proportion (95% CI).
*Participants in the KNHANES IV,V.
†Estimated Korean population weighted by year.
‡The cotinine levels in 2009 were obtained in a half sample of participants.
§The χ2 test was used to compare smoking status and date.
¶A urinary cotinine level below 0.01 was considered to be undetectable.