Table 2

Smoking prevalence rates of Korean school-aged children and adolescents from 2008 to 2011

KNHANES IVKNHANES 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 730p Value§
Current smoking
 Self-reported smoker with cotinine >100 ng/mL6.7 (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/mL1.1 (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/mL4.8 (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
 Subtotal12.6 (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/mL65.7 (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/mL0.4 (0.0 to 0.9) 00.2 (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)
 Subtotal87.4 (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.